My Zada had this problem not long after I got her only to find out I wasn't washing around the vulva well enough to get it clean. Now to describe why cleaning hers is different than Azrael's. "Picture this"
..... say you have a little marshmellow and you stick a bean down into it, but not to cover the bean. The area beside the bean is a bit deep, and you have to actually push the bean to the side to wash down in the groove all the way around. That's the best I can come up with to explain how the vulva kind of has a little groove around it. Azrael's doesn't, and neither does Raziel. Zada ended up with those little scab looking things that was just built up pee and such stuck to the skin before I actually noticed. Now I make sure I take the little wash cloth and wash that area before giving her a bath.