I just tried to convince her to take him to the vet, she told me I was being stupid and to stop getting upset. She protested that he has "always" had this bump, which is a total lie.

I just don't know what to do, she's not listening to me and she just brushes away everything I say. I told her that I won't be able to relax until she takes him to the vet but she still didn't care.