ATTACHED IS A PHOTO OF THE UNIDENTIFIED MARK

The other day me and my boyfriend were messing around and I saw a strange mark that looks like a hickey! I confronted him and asked him what it was.... the odd pasrt about his answer was that he had no clue what it is. We got into this huge argument and he was stupid clueless about his "bruise/scratch".

Clearly, let's say it were a bruise, the neck area being a sensitive spot... wouldn't you feel if something hit you or..punctured the skin hard enough to cause discoloration? I don't know what to think right now. I'm scared but I'm trying to keep my head composed.... please help me out somebody!