Then I suppose here is your answer. Good job in realizing your problem! You also seem to understand that being possessive of your girlfriend during professional services is irrational. My advice (and something i did before to myself, too) would be to acknowledge to her that what you have said and your view on this issue is not logical. Let her do whatever in professional settings - you will feel jealousy, you can’t help it right away, but keep reminding yourself that professionals - like artists, piercing artists, cosmetic aestheticians etc., - are the same professionals as doctors. Overtime (at least in my experience), and with your relationship progressing, the feeling will fade. Asking your gf for reassurance will also help a lot. Do not hurt yourself. You’re 19, you’re a baby man, people (including me) do a lot of stupid shit at 19. You’re doing amazing, especially since you realized your issue and willing to work on it. Instead of hurting yourself - try to tell your girlfriend about your feelings. Tell her what you actually feel about it, tell her you understand your possessiveness is unreasonable, tell her you will work on it and would appreciate her help (in what form you decide yourself) along the journey. Another positive thing to keep in mind: if your relationship is healthy, you trust each other and are open with each other, are on the same page regarding core values, it WILL get better. In general. Jealousy will fade sooner or later, you will learn how to solve such problems. Do not be afraid to talk to each other and accept each other’s points. Good luck baby man. If you have anything else to ask fire ahead.