my lil ole cat has a lump!

my boyfriends 10 year old cat, Sassy has got a big lump at the base of her tail.

last week i noticed she wasn't moving her tail around very much, it sort of stayed pointing down which is very unusual for her. and seemed like she was hiding from me, she wouldn't come to eat when i called for her, which she normally does. it wasn't until a day later i realized a small lump at the base of her tail, it didn't seem tender to the touch but it was really warm as if it might be swollen, and not a growth.

i'd told my boyfriends mother about it , but she didn't seem too worried about it.

Sassy is an indoor/outdoor cat and i was wondering if she had gotten bit by something? today the lump is twice the size, big enough that the fur on her back is sticking up, im so scared for her

he has been napping in the same spot since yesterday...

anybody have any idea whats goin' on? im going to try and make an appointment at the vets office tomorrow, but is there anything i can do for the time being?

Hi there, do you have a vet you can go to?

The things they will ask-is it red and puffy?

Does it have odor from it? of course not poo odor since its near her rear end. Absesses have a nasty odor to them-according to my vet-does it bother her? you can try to put a cool moist clothe on it if it bothers her or see if they will see her today. If it grew overnight I would recommend getting her in today. Does she have a fever? What about her vitals=pee/poo/eating/drinking?

she has been eating, and she uses the bathroom outside away from the house so i cannot tell what her bathroom habits may be. i've just put a cool rag n her, shes curled up tight in our guest room.
i gave the lump a gentle poke, it feels as if its full of fluid... :-:

no fever, and not much redness in the bump...

After dinner my boyfriend and i got home to find Sassy in bed licking an open wound, the bed had a small amount of blood on it.

shes got an open hole in her lower back, my boyfriend mom is taking her to the vet tomorrow, i there anything i can do to make her more comfortable? 

she keeps licking at it, is that alright?

heelpp

im so scared , and quite squeamish when it comes to blood ..

It's good that she's going to the vet tomorrow. My guess is an abscess that has now ruptured. Since she is an indoor/outdoor cat it is very likely due to a fight. You could put a warm compress to help with the drainage.
Just to emphasize that I am making a guess to what the issue could possibly be so it is VERY IMPORTANT to see your vet. If it's an abscess then your kitty will be given antibiotics.

after searching the web for similar stories i belive an abcess is what it was, thank you all for helpin'
she has an appointment today!

You are very welcome!