Confuse them....

Tell them "Hah, I pranked you guys. Can't believe you actually believed it."

You tell the truth, and face the consequences.

That is what adults do, and that is what REAL LIFE is about.

I lie to cover up another lie or I make a joke about it

That's what you get if you tell tall lies I'm afraid, there's no point in running from it, if you don't have a girlfriend, who cares? It's got nothing to do about what your friends think, but you need to admit that you were just talking sh1t, it'll be just more of an embarrassment if you pile more lies onto the others

Just confess and make a joke of it. Also not to sound cliche but if your friends are bullying you then they aren't real friends.

When you're caught in a lie, the trick is to tell more lies. You lie bigger and grander than ever before, you lie so much that even you cannot tell the difference between the lie and reality... Because if you can't tell, how could they?

You do that, and your problem will be solved!