I have had psoriasis since I was 4, recently I followed a treatment with clobetasol and now I have a lot of red stretch marks, what can I do?

Striae. Long term use of topical steroids can lead to atrophy or thinning of the skin. Stop using the steroid, there are non steroid based alternative treatments for psoriasis. Protect this thin skin from the sun with spf 30 or higher, and see a dermatologist. Certain topical retinoids like tazorac (tazarotene) can decrease the redness and thicken the skin. Certain laser treatments may also improve the color and thick.