The Past Couple Weeks Ive Been Snorting And Smoking Meth

The past couple weeks Ive been snorting and smoking meth and staying awake for 2 or 3 days eating a couple bites of one thing the whole day or not at all. When I work out I dont push myself too hard but I do sweat exsessively. When Im going a few days sober I smoke pot so I can eat more and gain back my weight. One day I started noticing some change in my skin. I see underneath looks weird like my veins are tiny at the surface and I have dark spots like bruises on my knees? Is it because the meth ?