Lately I've been having bad rashes on my arms, what could this be from?

There are both serious and not so serious causes of rashes like the ones you are describing. I think the first step is to sort out whether the rash is serious, and your primary care doctor can help you do this. In particular I am concerned about your history of drug abuse and I particularly want to know if you have ever engaged in injection drug use. This is because injection drug use puts you at much higher risk of infection with hepatitis C and HIV among other things, both of which can be associated with severe skin rashes. Therefore, I highly recommended getting checked out for these if you have this history. In the absence of a serious medical problem, then it is likely that you are just dealing with a bad case of eczema, which is a very common cause of skin inflammation, redness, itching, and cracking. The mainstay of treating eczema is moisturize your skin very well. It is best to use a thick, greasy moisturizer such as a petroleum jelly product. You also need to avoid scratching, and an over the counter steroid cream might help. I suggest seeing your primary care doctor to help you sort all this out.