Someone dared you to makeout with a guy so you did... I can not believe that anyone is so subservient that they would essentially sacrifice any and all trust in their relationship over a dare, so I am going to assume your horny, missing the physical relationship with your boyfriend, and regret your decision to makeout with some other guy.
If that last point is false, then the solution is simple, tell your boyfriend that you care about him and wanted this relationship to work, but not under long distance circumstances. Do both of you a favour and breakup.

If you do want the relationship to work, then I suggest you own up - and expect him to be rightfully angry, hurt, and mistrustful of you - & to quite likely dump you. If he does, then that is the consequence to your actions so i suggest you learn from it. If he is prepared to work through it with you, make sure that a long distance relationship with this boy is really what you want, because in the future you will have to exert far more self control and place preserving your relationship above sexual desires.
Long distance relationships are unquestionably hard, you need to decide whether or not its worth it.

All the best,
C

Why did you do it if you are so worried about it now???:confused:

Yeah.. The only thing to do is tell your boyfriend and apologize. Then hope for the best. You did a foolish thing and now you have to take responsibility for your actions. Next time, don't go kissing a guy, even if it's a dare.

Lol @ people who take truth or dare games seriously. You could have simply rejected it. Why did you do it? You're going to have to tell your boyfriend because you're hiding something from him.

wtf? "the same thing happened to him" i'm sorry how does this even make sense...lol