Hi and welcome to the forum. It depens... does it hurt when she does it? If it does, you need to teach her to be gentle but, if it doesn't hurt, let her do it - it might be her way of being affectionate. Zoe, my female Senegal, does the same thing but only on the outside of my lips and it doesn't hurt at all. She kind of rolls' the flesh between her upper and lower beak. Parrots would normally show their love by gently preening our hair and skin but some of them have their own way... Another example is Sophie CAG who presses the tip of her beak against my cheek and makes a human kissing sound several times in a row, and then there is Epuish Caique who shows his love by flying to my shoulder and rubbing his head first and then his entire body against my neck, cheek and shoulder. Some of them can be very quirky.
But eating paint is another story because it could mean that she is lacking minerals. Is her diet supplemented with vitamins or do you feed pellets? I don't like pellets for them, especially for conures, but they do have vitamins/minerals. I feed gloop, raw produce and nuts with a bit of a grain/seed mix for the budgies but I also give them a supplement 3 x a week.
