I think the best general approach would be what most girls are saying, put her on block, dont breathe a word of it to anyone, and go on with your life. I would strongly recommend that no matter anything else.
For me its a bit more complicated though. Ive had a couple of people I know IRL find me on cam - and both times they made it known to me while I was on cam (btw not recommended at ALL no matter what). My reactions to them depended on my relationships with them IRL. Seriously, go with the above idea to forget, shut up, and go on. But these are how my stories worked out for me...
Guy A found me on cam, immediately tipped for a friends list add, and privately told me who he was and how he knew me. He was a guy I fucked a few times, nothing anymore than that, we were never close friends or dated or anything, didnt have mutual friends, and it was maaaany years ago and we had lost all contact. I didnt mind that he had found me because we had that type of relationship, and I knew he wasnt creepy/malicious/insane. He asked if I minded him being there, and I said I didnt. He tipped for games, flashes, videos, etc. and it was fine. He didnt make any attempts to re-enter my personal life after that (outside of offering to be a stunt cock if I ever wanted to do b/g vids), and him being on MFC was just kinda like picking up where we had left off - as occasional sex buddies. He was polite, respectful, tipped for the things he wanted, and that was that. In fact I quite liked having him around, I got amusement from knowing he was able to see me and buy videos so he could "relive" having the girl who took his virginity.
Guy B found me on cam, started chatting in my room and acting super weird (didnt tip either), hung around for at least 10+ mins while I was carrying on as my normal self doing flashes and sexual things (which I NEVER would have done had I known he was watching). Eventually I clicked on his username and he had a picture of himself as his icon - and I FREAKED. Hes someone Ive known since I was 16 (so for a decade), is a close friend with TONS of mutual friends, is a huge drama llama, and hes made it super clear to me over the years that hes always wanted to hook up with me (to the point where its made me super uncomfortable because I am not attracted to him in that way at all, but he keeps trying despite knowing that). I was startled and upset to the point I immediately logged off and messaged him asking WTFH?! Basically he said he wasnt surprised to see me here, he uses the site and has a lot of model friends, and he tried to delete his user pic so I wouldnt see it and freak out - which made me double WTFH because it really seemed like he wasnt going to tell me it was him and didnt want me to find out.
It was really rough and I had to tip toe around it because he lives for drama, and all of the mutual friends and everything could have made the situation REALLY bad if I let it get too heated - but I basically told him it was NOT okay for him to see me on cam, and he really should have straight up immediately told me it was him if he absolutely couldnt resist coming in my room. I banned him, but it didnt end that easily. He followed my camming twitter with his personal one (the same one that a ton of my other friends also follow), and that led to another WTF NO conversation that he seemingly couldnt wrap his mind around (for real, he couldnt understand why I wouldnt want him to see that shit). He kept bringing it up when we talked, and would boast about how he knew ~*so many models*~ personally and he was shooting content for them, and he would be more than happy to shoot for me also. (lol side note: hes no better than just any dude with a point and shoot flash camera, and he wanted a cut of the money I made from whatever he shot also. Im sure he just wanted an excuse to watch me get naked and diddle myself.) That was over a year ago - I dont talk to him nearly as much now, and I cant remove him from my life without MASSIVE DRAMA - so I just kind of ignore him. He still tries to bring it up and talk about it whenever he can though. UGH.