One of mine does this. When you pet him he loves to groom you in return. Unfortunately, every now and then he'll mix the licks up with little bites. Usually they're very gentle, but every now and then he goes overboard. It's a little nerve racking, because you can't tell if he wants to lick you or bite you.
Shark will bite on my ankles when she gets hungry or impatient..and she does this on a daily basis without leaving a scratch on me....which seems a little odd.
I find once I have pampered her, she will purr at me then continue as though she didn't bite.
I can imagine your kitty is just being playful, and showing you that she is happy.
Don't worry about my kitty..I think that is her own way of getting a bit more attention off me!