Penetrating my partner hurts her, is there a cause to worry? i'm a lesbian and uses toys when we intercourse, we've been doing it for years now

Possibly: If she has a new onset of pain from penetration, then she should definitely have an exam by a gynecologist. It could be a number of factors causing her pain from vaginal dryness to infection to irritation or allergy to one of the products you are using. She should definitely seek care, and have a complete exam so the cause can be discovered and penetration can once again be enjoyable for her.

Be careful : Selecting the kind of sex toys used and you may need to use more lubrication. She may need to be checked by her gynecologist.May have hormone issues.