Mid-case pitting, what to do

[studioal]

Hello,

I bought this '89 79090 about 8 years ago and had it serviced after seeing some fog under the crystal. My watchmaker did the full service, but wasn't able to get it to pass even 1 BAR on his pressure tester. He attributed this to the rust and subsequent pitting that had formed on the mid-case where the crystal contacts it. He removed the pitting with his lathe and was able to get a pass @ 10 BAR. However, it's been left with some unsightly degradation where the pitting was/is that I can see through the crystal just outside the rehaut.

Is it fixable? I wonder if the case could be microwelded and refinished. Any idea what something like that would cost? It doesn't bother me too much, but I was thinking that if I ever wanted to move this watch it would likely bother someone and/or greatly impact the value.

You can see that bright dappling on the perimeter of the crystal in this photo best.