two strange lumbs!!!

my 4 month puppy (German shepherd) had two lumps on the end of the tails, and they're identical. we have taken him to our local vet, and she says she has never seen something like it before, it's not cancer, and she thinks it might be a blood blister. She has taken blood sample and puss doesn't come out of it and she says it's not cancer.  could it be chemicals, we put some flea stuff on him, and prior to that a six year old girl rode on top of him....if you have any questions feel free to ask and is there anyway i can upload a picture of it? oh and it looks like if he were to have a bamboo but on top of his but....it's pretty funny looking..and he doesn't show any signs of pain.

[Aleda M Cheng, D.V.M., C.V.A]

Without seeing the lesions it sounds as if they could be histiocytomas which are benign dermal masses that occur in young dogs.  They can occur singly or in multiples. These lesions resolve on their own in 3 months or so.

I will evaluate further once you have uploaded a photo.  

[xxunderseaxx]

so i should not drain them, oh well my dad yesterday took him to another vet and they wanted to drain him. the thing is we think it might be growing again?

[xxunderseaxx]

i don't thing it's histiocytomas, thee lumps aren't small they're like as big as breasts on a women. Extremely noticeable

[xxunderseaxx]

how do i add pictures???