Molly Young, 17, recalled how her tights “started to disintegrate” after she reached up to fetch the instrument from a shelf and the acid poured on to her right leg.
Molly was attacked by Emily Bowen, a fellow pupil at Knox Academy in Haddington, East Lothian, in September last year after Bowen discovered she was dating a former boyfriend. Bowen, 18, was sentenced to 21 months in prison for the crime.
Molly, speaking for the first time about her ordeal today revealed she still cannot feel parts of her leg.
She said: “I came back to school from an appointment and I had music class, and one of my friends said to me ‘oh, you’d better go up and check your viola because I’ve just seen Emily in the string room’.
“I said ‘let’s go and see what’s happened’ and I got half way up the stairs and I turned to my friend -- I had a really bad feeling -- and said ‘would you be able to come with me?’
“We went upstairs together and as soon as we went in to the room there was an eggy sort of smell -- we just made a joke about it.
“I remember looking at my viola and shrugging my shoulders, and I was like ‘there’s nothing wrong with it’.
“I just took it off the shelf like I do three times a day, and my tights just started to disintegrate. (The liquid just) fell out the bottom.
“When I saw the holes in my tights I was like ‘what’s going on?’.
“It was like someone holding a blow torch to your leg.
“If you burn your hand on an oven you can take it away and run it under the cold tap and it’s fine. With that I couldn’t really pull it away because it was stuck to me. I didn’t know what to do.
“I just ran out of the room to get help, and it kept burning.”
Molly, who was screaming in pain, told how a teacher “dragged me in to the staff base” while calling for an ambulance.
She said: “She took my boot off and I stood in the sink and she just used the teachers’ mugs to irrigate it.
“I was saying ‘it’s so hot, it’s burning’.”
Molly, speaking in an exclusive interview on ITV’s This Morning, told presenters Ruth Langsford and Eamonn Holmes how her right leg was scarred, while her left leg escaped with “a couple of splashes”.
She said: “It looks like a birthmark now to be honest, but to start off with it was full thickness burns so I still can’t really feel certain parts of my leg.”
She said she thought Bowen was responsible immediately, and her suspicions were later confirmed by a police investigation.
She said: “I had a feeling when it happened but obviously I didn’t know for sure because there was no evidence at that point.
“I’ve seen her like twice since it happened.”
Molly, who was looking forward to completing her exams and leaving school at the time, revealed she suffered from post traumatic stress after the incident.
She said at one stage she was unable to perform simple tasks like tidying her room, without help from her mum.
But she said that, following counselling, she is now looking forward to starting an apprenticeship at a top restaurant.
She said: “It was quite hard to start off with because I went back to school on the Monday -- I felt like I needed to for some reason.
“It wasn’t until about January or February this year I started feeling the proper effects of PTSD.
“I couldn’t concentrate on anything. It sounds silly but I would start just screaming for no reason -- because I didn’t know what was going on in my head and I felt really frustrated.
“I didn’t know how to get my frustration out. I remember one time I went up to my room to clean my wardrobe and it was such a simple task but I just couldn’t do it. I had to get my mum to help me.”
She said counselling had helped her come to terms with her situation.
And, in another positive step, she revealed she may soon resume playing the viola, after she took a break from playing the instrument.
She said: “It was good just to be reassured that what I was doing was ok -- my reactions were totally normal for someone suffering from trauma, which was comforting.
‘I’ve finished school and I’m starting an apprenticeship next month in a Michelin starred restaurant, just doing front of house so I’ll learn all about wine and cheese.
“I’ve had a wee break from viola, so I’ll probably go back to it at some point soon.”
Speaking presenter Holmes -- who described the attack as “the wickedest of crimes”, she said she believes it should be harder for young people to buy acid.
She said: “It is a weapon. It’s a really corrosive substance and does so much damage to people. I just don’t understand if you are buying it online, why can’t there be a little red flag or something that comes up just to say ‘do you have a licence’ or something?
“Why would a 17-year-old girl, for example, need to buy a bottle of acid, or drain cleaner?”
Bowen, 18, whose father is a QC, was jailed at Edinburgh Sheriff Court for 21 months.
The court had heard how the girls were both talented musicians, with Bowen playing the clarinet and Molly the viola in the school orchestra.
Bowen, who was due to study law at Aberdeen University, poured drain cleaner containing sulphuric acid into Molly’s viola case after discovering Molly had started dating a former boyfriend.
The court heard that Bowen had also written a fake letter from Molly to herself demanding that she end her own life. Sheriff Michael O’Grady referred to Bowen’s “careful and premeditated actions”.