My rat, Meiko...

I have not had my rat for very long, I would say about three months. When I got her home from Petsmart I realized her back right foot was swollen and red on the top. (Almost as if her knuckle was broken) I immediately took all toys and such out of her cage so it could heal. A week later it looked like it was rotting. The day after I noticed I took her back to Petsmart. One of the ladies up there told me to apply neosporin to the infected area everyday. I also noticed that her fur was thinning, I figured it was from stress. (Meiko and I move around a lot.) I let her rest for a couple of weeks her fur stopped balding and her foot looked a lot better. I went out of town and left her at a friends. When I came home her foot was scabbed over. I figured that was a good sign and just to let it be. It's been awhile and her foot is still scabbed. Her two front teeth look as if they are too big for her mouth. Also her paws are either scabbed or just dried blood I can not tell.. My most resent discovery is that her tail is discolored (White, and a darker color of her natural skin color.)

She eats and plays normally.
And her behavior hasn't really changed.
But I am really worried about her physical appearance.  

I plan on taking her to Petsmart again but I would like a second opinion.
So what do you think is wrong with Meiko?

[Cami1125]

I would say take it to a vet.  I had a rat who had a tumor, we didn't do anything, had to get it put to sleep.  I know it doesn't have a tumor but you really should take it so it doesn't get out of hand.  I really hope this helps! If you ever need any rat info. email me at ***@**** and I will be more than happy to help! Good luck! :)