What happens after you stop breastfeeding?

I want to bring down my milk production just a little because I have been getting mastitis every 2 months since March. My doctor suggests cutting her off or pumping. My pump is missing a part so thats out of the question. Now I'm thinking my next move could be slowly weaning her off by slowing down my supply. Any tips on how to slowly dry my milk?

I have another question that I can't seem to find on other forums. What happens when you just stop breastfeeding? What happens to that dried milk? Does that cause any issues in the future? When I don't feed after 2 hrs my boobs get rock solid, so I'm wondering how you get that rock solid milk out or where does it go?