I have a setback story from waaay back in the day.
When I was in junior high (1990ish) jheri curls were the hot thing and I pleaded with my mom to let me get one. Prior, I had a nice, thick APL press n curl, and she tried and tried to talk me out of it, but I was tired of having to get my hair pressed, and always worrying about it reverting. After having the jheri curl for about a year, I was ready to go back to my natural hair. The stylist at the salon told me that in order to "reverse" it, she would just wash out the chemicals, blow dry it straight, and send me on my merry way.
When I tell you guys that I had MASSIVE shedding... my hair was coming out in handfuls! Every time I ran a comb thru it, it was full of hair. My hair got so freakin thin over the course of about 3 or 4 weeks, and to make matters worse, everyone kept asking "uuggh, what happened to your hair? it used to be so long and thick". My mom suggested that I get a weave (it looked just that bad)... but back in those days, weaves were looked at with disdain.
There was no way in hell I was gonna be caught dead with a weave and ridiculed by my peers.
To make a long story even longer
... after a year and a half, my hair grew back so that by the time I was in my junior and senior years, it was long and lush again.
I can definitely look back on this story and laugh now!