A boy I was dating asked me did I have scabies?

I had seeing this lad for a while at new years but then stopped. We got back talking and he asked me on date so we met up but he asked me did I ever have scabies (which I never have btw) because he got a rash like a month later after he stopped seeing me. He said he didnt get with anyone else other than me at the time. I was highly insulted because I never had it before and i feel its very embarrassing.. am I right to be mad at him?