He hid a hickey and lied!?

Okay I know this is gonna sound a tad childish. My friend and I are really close and everything. We tell each other almost everything. But when I spent the night at his place last night I notice he had a hickey and he kept trying to cover it, either by wearing his winter coat in the house and when he decided to take that off he put on a sweater with the hood up and zipped up so it was almost tight around his neck. I notice it when he was playing the drums cause that's when he took off his winter jacket. I'm just a tad confused on why he wouldn't tell me about this and when I ask him if its a hickey, he lies about it and said he got it from wrestling. Like why lie to me?