What should I do about HiiM?

I went to my friends-18years old(mums bestfriends daughter) house the other day who was having a party for her friend’s birthday he was turning 16.. Before the party my friend and I was just talking about who was coming,and she mentioned the boy who’s party it was.. Was fit..but had a feature on his face which put her off,she notified me that this boy had been liking her for 2 years. I was just listening to her. When everyone arrived the birthday boy was sexy! At first the feature of a birth mark kind of made me like erm..

So that night me,my friends brother,the birthday boy + 2 other boys.. Went out and went to the shops,while my friend stayed at home with her sister until we got back as it was late.

I grown to like the boy,for who he was,even though he was hot-sexy. When we all arrived back to the party he asked me if I had a man and I was like no,and then everyone was looking at me to say get-in-there,we sat down on the sofa and was watching tv and he asked if he could talk to me outside,I relunctantly agreed,my friend got abit envious by this :/, he then asked me out I said no,but didnnt ggive any reasons.. We then kissed in the rain.. :d. But I still said no why did I say no,I have no idea The rest of the evening my friend was really upset,even though she went into the bathroom with another boy for an hour!. She asked me what birthday boy had said.. I just said we spoke..I didnt dare tell her we kissed,because knowing him moving on from her might have caused her to be a bunny boiler. But I really like him,and im not sure when im going to see him again, But my friend told me he used a girl for sex. :/ But the my friends brother was like I think he likes you cause he keeps watching you..and I really like him,but I dont want to be upfront and stuff.and I defo do not want to say because my friend I can see going ballistic..even though she hasnt said anything.

What should I do?