Talk to your doctor for clearance to play. You may feel you can play through the pain, but you don't want to turn a moderate injury into a more serious one that later requires surgery. Get a proper diagnosis so you can make an informed decision.
Take anti-inflammatory medication. This will help alleviate pain and reduce swelling.
Warm up by walking. Don't cheat and say you'll take it easy for the first few holes. Give yourself 20 minutes to prepare your body for your round of golf. Start with a brisk walk to warm your muscles up.
Continue warming up by proceeding to stretch your major muscle groups. Stretch your back while sitting, not standing. Bending to touch your toes places more stress on your back. Sit down and work through bending forward with your legs in front of you, repeating the stretch with legs both together and apart, and take your back through a full range of motion. Don't stretch past the point of pain.
Play a short course, something that is a par 3 or 4 without many long drives. The farther you have to drive the ball, the more twisting you will do, and the more stress you will place on a herniated disc.
Stop immediately if you suddenly feel sharp pains shooting from your back down to your extremities.
Ice your back immediately after playing.
Rest for at least three days before playing another round. Do low-impact activities in the meantime, including ample stretching. Continue to take NSAIDs as prescribed, and use a heating pad if it helps reduce pain.