Is she swelling for a heat? If so that is why as they lick alot coming into heat swelling first week, then second week is drip of the blood. they lick then so watch her.
she could have a urinary infection, might want to have a vet look at her as females get this and could be serious if left go. Might want to dab some perxoide on there to sooth and release any bacteria for the moment, see if it helps any? It sure will not hurt her. good luck...