If your dial was silver when you took it in....it didn't change to pink in the shop because of water leaking into the case...The dial could be discolored by a leaking crown but it would have looked pink when you took it in. If this is very noticeable I would seriously question the repair man and the manager of the shop. If it was discolored when you took the watch in then it really isn't their fault. If it looked like it did when you bought it when you took it in for service and looks different now....somebody messed up probably. Check it out.

Best,