Have a swollen vagina lip, a itch and a fever what can it be ?

You need an exam: And pronto. The first thing that comes to mind is herpes, but that's only one explanation. The Bartholein's gland can become infected and enlarged, you could have a sebaceous gland that is blocked, infected, and myriad other problems. That you have a fever is what is the most worrisome. You need to be seen by a physician today. Please call your doc and follow their advice.