minor burns from salon machine

Firstly, a big thank you to anyone who takes the time to to read and/or help me with a response.

My girlfriend was recently at a saleon where she was having a facial treatment. The lady doing the treatment had set up the machine next to her which was heating up wax. the lady left to sort something out or fetch something, and while she was away the machine exploded with boiling hot way flying everywhere. a large blob landed on my girlfriends chest. This caused huge ammounts of pain and left her with a fist sized blistering scar. She went immediately to A & E where they treated her for minor burns with a gel and dressing. The burn was very painful for a while and the scar lasted for around 3 weeks. It was in the summer and meant that she had to keep it covered, when everyone else was in swim suits as she was embarassed by it. She works in the fashion industry and found it difficult as how she looks is important (as terrible as that sounds)

She is thinking of making a claim, however is unsure if this is worth it. How strong is her case? And what is a vague estimate of the kind of damage settlement she is likely to get.

Many thanks,

Oscar