When that happened to me I'd pump just enough to relieve the worst of the pressure. Things did regulate eventually, but having had mastitis with Josie, to the point where by the time anyone would prescribe me anything I was too sick to get it (Thank God for DH!), I was in no hurry to risk it again, so I decided to go ahead and at least pump the foremilk just to keep the ducts open. (I did decide not to give just the foremilk in a bottle though; I think I had it over cereal, mixed with regular cows' milk!

)
Not saying that was the best option for anyone, but it worked out OK for me. I'd say if you take that route, just make sure you aren't pumping right to the end, just to let pressure off.