My roommate treats my dog badly

I have had my dog for about 4 years now and my cousin has moved in with us two years ago. It was kind of last minute but I had to deal with it because she’s family. She moved in and I let her know that we have a dog, my dog sleeps with me. I’ve only ever met her when she moved here and she has begun to treat my dog kind of badly, she gets showers every week and is a very low energy dog, unless she hears a doorbell. Other than that has not really done anything to her or her possessions. However every time my dog gets on my bed she shoos my dog says terms like “don’t try it” “don’t you ever” and dusts the sheets like shes tainted or something. I’ve always never minded her not wanting her on her stuff ofc it’s a dog, but I feel like the phrases and insults are just over kill when she could signal her to get off the bed. What should I do about this? Or am I overreacting