Welp... Made things super awkward with my boyfriend's son

My boyfriend's son is over for the weekend. He likes to mainly stay in his room and we don't talk a whole lot. He will say hi, and I will ask how he's doing, and we will have conversations but he is more of a stay in his room and play video games type of person. I had a question to ask him. I don't even remember what it was tbh. I have small children so I never knock on their door. I just go in. His son's a teenager and because I'm so used to just walking in my kids room I just walked in his to ask him a question and he was... touching himself... I understand masturbating is normal but it was always looked down on when I was growing up and I have young children so I haven't had to deal with it. I know it's normal but it just makes me uncomfortable. I didn't know what to do so I slowly backed away and closed the door and now he isn't talking to me at all. Should I mention to my boyfriend what happened or just hope his son starts talking to me again.