If you stop milking her you could kill her. She is giving a very good yield, and because of that, if you suddenly stop milking her, she would almost certainly get mastitis, and mastitis, if severe, can kill. Definitely do not stop milking her. I know it is hard when they get sores, because it makes milking uncomfortable for them, but you need to persevere. If you do decide to stop milking her, you have to dry her off properly, reduce how much milk you take from her gradually, and gradually drop the number of milkings down.
I would recommend keeping milking her as normal, has anything changed recently about her routine? Have you changed her bedding or where you get it from? Has she got sunburnt recently? Our goats have been a little sunburnt on their udders over the past few days as its been nicer up here. Was she suckling a kid, and is not now?
Persevere with creams, we use E45, a healing balm made by a honey company. You could try aloe vera cream, it is always good too. If you need to get the sores to dry out a little bit, try a bit of veterinary wound powder.
Hope that helps, it can take a couple of weeks to get them healed up.
Beth