Ok, getting help or instruction technique here on TB is a great idea. Asking for opinions/reviews on TB is another great idea. TB, however, is not the place for medical diagnosis.
Now, just my $0.02, but from your description it sounds like you over extended the joint, or you just stubbed it real bad. Worse case is you've torn cartilidge (sp?). Just ice it up, and keep it in a splint or something for a few days. Then gradually start to work the finger on occasion but keep it splinted the rest of the time.
Now, put all that aside and take your happy-lil-rearend to a real doctor and get it checked. After that, decide which is more important, the dog or the cat, and get rid of the other one

. Good luck.