I had my eyelashes tinted some time ago and the salon insisted on doing a skin test before doing the tint. You hear nasty stories about people have bad reactions to beauty treatments and I would suggest having a chat with the salon to guage their reaction. If they deal with your complaint well and reassure you about their practices, then I would leave it there, but if they seem unconcerned, I would consider taking it further and complaining to a local authority, who may send someone in to investigate this further.
Cheers Sue