I started using Tretinoin several years ago when I started seeing some of the more significant signs of ageing appearing but stopped a little over a year ago when my I had some big expenses as my financial priorities changed. I started using it again a few months back but have noticed something strange.
When I first started using it, it made my skin very red and irritated and it took a while to get used to it. I had assumed that this time around it would be the same; that I would have to get used to it again given the extended break and there would be redness and irritation. There wasn't, however, and I initially thought that I must just still have the tolerance I originally built up and that taking a break hasn't made a difference. But then I remembered a time when I squeezed too much out of the tube and rubbed a little of the excess onto my arm at a time when the skin on my face was used to it. The tiny bit of skin on my arm flared up and was very sore and angry for many days. I did this again recently and I had absolutely no reaction - the skin on my arm has not gone red or irritated at all.
I'm beginning to wonder if I'm being sold fake stuff. I get it from a very reputable place headed by a well respected doctor that has won many awards so I very much doubt they would risk damaging their reputation by knowingly selling fake products. But could they be doing so unknowingly? Everything else about it is the same. Same packaging, same smell, texture, colour etc. What might be going on?