This HN comment thread is a day or so old so perhaps you won't read this, but as someone who had an L4/L5 bulge 14 years ago, my most emphatic recommendation is that you walk as much as possible.
Certainly you need to do all of the rehab/prehab strengthening exercises you can - and you need to do them for the rest of your life - but the real turning point for me and that back injury was beginning to walk regularly.
Your body (and your back) are built to walk. Walking will heal you. Yes, it might hurt more and be uncomfortable for the first week or three, but after that, everything tightens up and fires up and tones up ... and all the pieces of your spine put themselves back into place.
I am over 40 now and have been doing (relatively) heavy squats and straight leg deadlifts for the past ten years. Totally asymptomatic.
The sad thing is I haven't been doing a powerlifting routine at all. I decided a couple of years ago when I started lifting that I'd rather look good than be able to lift super heavy weight. I was only deadlifting about 1.2 times my body weight.