Is he cheating ?

My boyfriend and I have been together for a 2 and a half years with no arguments as of yet (we always try to communicate and listen to each other’s concerns) and we are completely in love. I don’t doubt his love for me at all because I can feel it from him and he treats me so well.

About three days ago was his 21st birthday and he invited my family over to his house which we were excited about because they’d get to meet the rest of his but I noticed he had a turtle neck on and one of his aunts asked him why he was wearing it when it was so warm out and pulled it and I noticed a mark that looks like a hicky in his right side and he quickly hid it.

I did speak with him about it and he said it was from paramedic school when they were practicing how to put on neck braces or something like that and that he hid it so no one would get a misunderstanding but it still left me unsettled. He did reassure me and said he would even tell my family Like I said, we tell each other everything and the fact that he didn’t tell me this made me doubt him for the first time. Am I overthinking it?