I am in a similar situation now, my hair was neck length and in a random moment of insanity I cut it all off this summer (tapered back and sides). Of course now I have snapped back to reality and on a long journey to grow it back. The back and sides of my hair were relaxed every three weeks with a mild relaxer with no damage, but it was also trimmed regularly. When touching up the edges I left it on for less than the time called for, just enough to break the curl pattern and minimize damage
Now that I am growing it back, I have limited the relaxer in the tapered back area to once every 5 weeks as I will not be cutting it. I get a relaxer at 10 weeks, and then touch the short area up at 5 weeks post. with no damage (4a/b type hair). You can also try ORS Edge Control which works really well ,and very moisturizing and may help during that in between period
My hair in the back is now at the point that it is about an 1 1/2 " in length
erplexed and now I manage by putting Ecostyler gel on it and it curls up. I have been wearing roller sets so it blends better. I just had a touch up so I am hoping this will be the last time I have to touch up the back at 5 weeks post, and continue to manage by wearing curly roller sets on this very long journey. HTH.