Hi Claudia,
I am looking for the same service. As I know, Yanhee is one of the best private hospitals for beauty and they provide electrolysis service. However, their price is rather high. I consider to remove my hair there at the end of this year.
It is grateful if anyone would share their experience or information here.
Claudia, you should be in Bangkok now. I hope everything goes well for you. Wish you all the best.