My painted turtle keeps biting my red eared slider

Question
I have a 120 gallon tank with 4 red eared sliders and 1 painted. My newly mature painted turtle has shown interest in my very large female. Currently he is acting out his mating interest but I don't think she's interested. At the same time and my concern, he keeps biting at her face. Over the days I have notice more sores and redness on her neck. He does not bother the other turtles which are mixed male and female. My female acts like it doesn't bother her and never strikes at him but I'm worried an infection can occur and when he'll just leave her alone? Plus why is he biting her?

Answer
This is season for breeding. If you do not want them to breed then you can remove one or the other for a while.
She may or may not be interested. H eis biting as a ritual and is actually showing he is the male...
like a chimp will hit his chest.

He will not leave her alone until he is successful then odds are if you have another mature female she will be next ont he list