Thanks for everything that you are doing. 

I visited a CSW. I believe she is pretty cautious as she she put a condom on me the first thing we did together, so we performaed protected sex for oral. She claimed she got tested regularly. While she was on top and trying to help me penetrate, I got flaccid, and we realized the condom slipped off and stopped trying. I think the possibility that I ever penetrated was low beacuse I was not fully erect the whole time and I assumed either of us would notice and feel if I penetrated. Therefore, I think the penetration didn't happen and even if it did, it was probably in a split second. I confirmed with her and she said no. At the same time, there was for sure some contact of our genitals, something like frottage but unintentional, after the condom slipped off but before we realized. 

I also let her spit in my month.

Do I need to worry about anything? Any PEP needed? 

Thanks!