What physical effects after years of injecting opiates are there?

Tolerance: To narcotics. You will need higher and/or more frequent doses of opiates. Also, unless you have already withdrawn voluntarily form drug use (difficult to do by oneself, w/o any help) you will have a withdrawal reaction that could be severe but usually not dangerous. The physical manifestation are not pleasant. See a specialist that deal with drug addiction or pts that use high doses of narcs.