when changing the oil last time around i guess i cross threaded the drain plug. so while riding today the bolt for the oil drain fell out. i didn't notice and my bike wasn't getting hot. when i stopped at my truck i checked it and bolt be gone. but oil was still dripping out. the engine didn't seize or anything but i'm scared that i could have messed up the engine. also what do i do about the thread? is it simple to rethread something?