Finished treatment and hair has completely returned

I had a 6 treatment package that I finished about 3 months ago. It took a while for hair to grow back (Brazilian), but now it’s like 90% of it is back! What happened?! Has this happened to anyone else? I figured I’d have hair regrowth since 8-10 treatments is usually recommended, but towards the end, I was hardly growing any hair at all between treatments so I didn’t bother with buying more.

I spent almost $1k on the treatments so I’m pretty upset!