I had mine done over 10 years ago, thin top lip as well, and I‘m really happy I did it. I had one top up 6 months later and ever since my lip has never gone back to really thin again because the filler stimulated my own collagen and now I have just nicely balanced natural lip. I had Juvederm injection done by an experienced doctor, a small amount as I never wanted significantly bigger lips. The procedure was done under full dental block (injections into gums like at the dentist’s) so didn’t feel a thing. You can have anaesthetic cream applied for about 40 minutes prior but it can make your lips swell a bit so doctor can’t judge the result as well straight away. Botox hurts much less (different place of injection, smaller needle etc) and apart from wrinkles it can also help with certain types of headaches, as well as to reduce excessive sweating when injected in palms or armpits. I’d say one thing to avoid at all costs are Botox and filler parties, these are medical procedures no different to any other injection so you need to have an individual consultation including consent, where the doctor tells you in detail what to expect, side effects and asess your needs carefully.