This is so silly, but I can't help feeling irrationally annoyed. Background: my best friend became friends with a girl a few years ago, M, who for some reason took a dislike to me and was v.rude and acted really bizarrely/bitchy towards me. I just decided to ignore her and didn't socialise with her at all.
They later fell out after M flirted and practically humped my BFs DH while they were all on holiday together 
whilst continuously putting my BF down, making digs etc.
Fast forward about a year, and they are friends again. I don't like the girl, but whatever, I don't have to see her & I love my BF, even though I think this girl is abit poisonous.
BF has three kids and recently booked herself on of those makeover/photoshoot things, for her birthday. She asked me to come along ( I think a friend comes free or something) and I agreed, as I thought she needed moral support and wanted abit of fun, pampering time after spending every day with two small babies..no problem.
It's not really my cup of tea tbh, I find them abit tacky and cringy. Really don't want to be pressurised into buying expensive prints that I don't want and am usually awkward in front of the camera anyway.
Anyway (sorry this is so long 
best friend just put up pics on FB of a photoshoot she did on Monday with the poisonous girl. Poisonous has apparently started her own makeover business and BF went to model for her and help publicise it.
I felt abit sick seeing the pictures tbh. I know this is ridiculous - BF looks stunning, but its really put a dampner on own photo shoot at the weekend, and I can't really break down why. I think I'm being irrational, but I feel like, there doesn't seem much point in going, as she has just had the experience with poisonous girl anyway, so what's the point?
Should I tell her how I feel or just suck it up and go, regardless of how icky I feel about the whole thing?