Sorry, BLACKSHEEP46, but I couldn't disagree more. Not stripping the affected quarter is withholding treatment and condemning the ewe.
If you don't strip the quarter then yes you will lose the quarter. And for most of us, that means losing (culling) the ewe.
If you catch it early enough and
do strip the quarter
at least twice a day for as long as pus/bloody pus comes out, then you have a good chance of saving the quarter and hence the ewe.
I've spoken before about my own experience with one particular favourite Mule ewe - Judith. She did recover, and the udder appeared normal too. She did go on and breed again, and did produce milk from the affected quarter - but the milk was of reduced quantity and quality and she was unable to rear twins unaided henceforth, having previously reared triplets twice at least.
However, I know that we also treated and kept on other ewes who had had mastitis. So long as their udders recovered, we kept them on and bred from them again. We didn't keep such detailed records that I could say they all did or did not have reduced capacity henceforth. We topped up lambs who needed it; maybe we were always topping up lambs from ewes who had previously had mastitis, I don't know. The problem with Judith was that she wouldn't allow her lambs to be topped up, so the only option she gave us was to remove a lamb. I did that two years running, and then very sadly let her go.