Asked: Can I get demon possessed?

So today I bought an Xbox 360 from a yard sale. The people who are having the yard sale do psychic readings and there was a little boy there that looked like a demon. He had like black cat eyes it was really creepy. He was the sellers son. And when the seller went to go test the Xbox for me I went into their house. Could I have been possessed by demons at anytime I was in that location? I'm worrying so much but I know I shouldn't because if someone has Jesus in their heart, a demon can't enter. But what if one did? What can I do?