if she is a sex worker my guess is any blood on the tissues would be menstrual. use of contraceptive sponges, sea sponges, diaphragm aren't uncommon tools of the trade used to soak up/damn up flow .. cuz working ladies don't get a week off for the duration.
i will throw massive shade on your choice of sex workers. massages parlors are notorious for human trafficking. the women are imported, are indebted and usually have no family ties/alternatives in their new location.
unless her limited english was a play on clients yellow fever, there is a very real chance her consent is nonexistent .
also.. hot asian fetish is ultra-racist. boohiss.
general commentary on dudes making a woman bleed.
one, she has an infection.
two, she wasn't aroused enough to be properly lubricated.
three, you are a terrible lay.
very rarely has anything to do with size unless the bleeding is from tiny forchette tears. the vaginal equivalent to paper cut + lemon juice.
if you are concerned about ya approach to PIV sex. slow down. pay attention to her body. opt for a high-end/glycerin free lube, apply liberally and reapply often. be mindful of your angle of penetration and your depth.