I like that last one: rest as much as you play. The older I get, the truer that is. But it is hard to do, when one wants to get better and play more. So the different kinds of practice suggested by Rowuk are one way around taking time completely off and taking a whole day off another. Both should work. Also, are you doing any cool down after these gigs--long low tones, pedals, etc? The finish to any hard work out should include a cool down to help get rid of lactic acid build up in muscle from the workout. And, how about icing for awhile when you get home from the gig? Should help reduce swelling. Guys I know also take ibuprofen to reduce lip swelling.