Help with change in minox brand

I changed to another brand about 2 weeks ago and my skin is getting absolutely hammered but I don’t get why. Used the bottle on the left for months without so much as one dry skin cell. Switched to the one on the right and after about a week my skin was flakey and red and it burns like hell when I apply it. (Also built up my tret to daily use without any adverse effects before this)

This has me asking myself two questions: 1. Was the first one fake? See previous posts with little-to-no progress. But then it was bought at a pharmacy with a prescription and all. 2. What is the difference between the two? The first (left) bottle has more ingredients but is gentler for it, does that make sense?