This may be nothing more than bruises after minor injury -such as playing too rough.
But my instinct is that you should take your dog to the vet for a complete blood work-up, and examination.
There may be a decrease in platelets, and it is important if so, to find out why. And to find out if there is any decrease in blood clotting time. This is quite easy to test.
A visit to the vet is the best thing to do.
Sorry....I meant to say, "if there is any INCREASE in blood clotting time"
Welcome to the forum.....These don't look like blisters to me! Personally, I suspect a bleeding disorder.....You need to have your Vet run a full blood panel and look for abnormalities.
I wouldn't wait, because in case of a serious injury, she would bleed out before you could get help.....Please, come back and let us know what your Vet says.....I'll be interested......Karla
Agree with the above. Best to have the Vet check this out as there are diseases or clotting disorders that can cause this. Hope it is nothing serious