Drugs for Psoriasis

I am a 19 year old male, and would like to warn anyone with psoriasis about a cream called Diproderm. I was under treatment for severe psoriasis, and I was prescribed the hormonal cream, called Diproderm, by my doctor. Sadly, the cream had the side effect that it weakened the skin, and it made me gain wait. After 2 weeks of using it could see stretch marks forming on places. I stopped using the cream, but it was too late. The stretch marks continued growing, like cracks in ice, and I now have horrible stretch marks on about 60% of my body,including legs, arms and "lovehandles". The stretchmarks are more of a psychological tear than physical, because I am now very self conscious about my body, and refuse to show anyone beside my partner any part of my body which is affected. On top of that I still have psoriasis, and worse than ever. I don't know if I should blame myself, the cream or the doctor.