Weird bump

I have a bump on my skin. It doesn't bother me but my mom is freaking out. She took me to the vet, which I hated. He stuck a sharp thing in it and then made me wait and wait. Plus I had to get my regular meds and a pooh sample. OWWOOO. I was not happy with my mom. The vet said it might be a histo something or other and should fix itself, but if it grows instead of shrinks I need to go back. My mom wants it to be nothing and my boy keeps trying to get me to go back. Why are they trying to torture me? I hope it disappears soon.