Best friend/Guy problem

Erica
Okay so my best friend met up with a guy from tinder a few months ago. They just hung out once and it didn't really lead to anything, because she said wasn't into him. 
I'm on her snapchat story and Instagram a lotttttttt and I guess he saw it and thought I was cute, so he followed me, and now we're talking and have been on one date. I made sure this was okay with her before talking to him, and she said it was because she didn't like him. She also told me that noting happened on this date. 
But I just found out that she gave him a blow job when they went out a few months back 🙃  I don't know why she didn't tell me this earlier...I'm honestly very grossed out and I feel really uncomfortable ESPECIALLY if we all hang out together. because I feel like there'd be awkward sexual tension between them....and I kind of really like this dude. Should I be worried or do I need to chill lmao help