Normal ?

So I’ve been seeing this guy these past 2 months , were still learning what eachother likes in bed. He’s big on boobs , I’m conscious of my boobs so only recently I’ve let him start playing/sucking my nipples.

Last time I did have to tell him to go a little easier because he was being a little rough for me because I have very sensitive boobs. But this time he was only playing gently and sucking on my nipples and it was very painful! and now I’m so sore there’s just a constant burn/hurt in my nipple and also found what I can only describe as like little green crusts (like something you’d find in your eye when you have conjunctivitis) I’m scared to let him do anything again! But I know it’s what he likes . What do I do ??