WTH keeps biting him

My boyfriend keeps getting bit by something in bed. It’s NOT bed bugs. He is the only one getting bit. He left for work for a month, I slept on his side of the bed and nothing happened. He came home 2 days ago and has a huge bite again and they are always hard and itchy. We can’t figure out what’s going on. Something apparently likes how he tastes because it’s the 3rd bite in 2 months. (The white is cortisone)