I hate when my girlfriend pops my pimples.
Why do you dislike it when your girlfriend does this to you?
I just feel like it is kind of gross. Also, it is an invasion of my privacy.
I can understand the situation you are in. You shouldn't let your partner do something you are uncomfortable with. I think you should talk to her and let her know what you are feeling.
I will nod, but deep down I'll hate her for it.
If you really feel this way about it then i don't think it would hurt for you to let her know. She can not change her behavior if she doesn't realize that it is making you upset. Maybe her knowing will motivate her to change her ways.