Bump between vagina and anus

Hello- today I noticed a weird bump between my pit mix’s vagina and anus. The bump is recent and was not there yesterday. I’m attempting to call my vet to set up an appointment but he has not answered the phone. I have attached a picture. It doesn’t seem to be bothering her even when I touch it. 

Hello!  Lumps in that area can sometimes include interesting (unusual / irregular) herniae but this looks more like a skin lump from this angle.  Your vet would be needed to confirm as much so we advise going to see them. Skin lumps can be caused by infection (eg an abscess or infected follicle), by inflammation or even by cancer (benign or more nasty) and a sample is sometimes needed to identify them fully (some limited samples can be taken with patients awake; others may need a GA).   I'm struggling to locate the exact position of the anus with the angle of the picture, so an inflamed or blocked anal gland may be another possibility. Either way, a vet visit to check it would be a good idea.  Please let us know what they say!

Take dog to vet asap if you are looking at this photo to see if it is what your dog has.  I looked here and found no answers so hope this helps someone. My dog had the bump aspirated with a needle at vet. It came back as a mass cell tumor. Currently looking into options for surgery/chemo.