The risk through oral sex even with cuts in your mouth are VERY SMALL. However i would still get tested to put your mind at ease, in the mean time i would relax as ECN said the tisk is almost non-exsistent.
Best wishes
I cant believe you went down on a women and didnt notice she was on her period, blood really have a taste, and also smell, sso you would have noticed if some blood got in your mouth, i assume you found some dark dried blood on your finger since you fingered her, so if the blood was dry then the hiv virus in that blood was dead, the risk of cunillinguis is only theorical so try to relax, its imposible to say if the blood was enough to be a real risk or not, I`ll sugest you go to and hiv specialist in your town and give him all the grafic details we cant see over the web, anyway just to calm down, I do think the risk is extremly low.