The problem is that there is a change in the constitution of the skin of everyone and change can be very delicate and whenever chane occurs old medication will not work as well as they used to work. I ofeten noticed that for the xternal medication for either the skin or the throat.
Its abot the fith time i am changing medication for my throat whenever i get the flu.
But on the contrary, i find out that for for oral medication its does not happen and that the body gets healed in some case completely. It was my case for acne where i was on roaccutane. Where my doctor proposed em a combination of external and internal treatment.
The external treatment consist mostly of creams like zenmed and swimming in the sea.
I had to drink about 4 litres of water a day.. pfff...
However my body did change radically and the acne has never risen since five years.