im not sure about the singing tingling feeling your describing. i get that when i IV large doses of morphine
sulfate pills, and its very unpleasant and hurts to me, only last 45 seconds to minute for me though. but ive also read here thats common when IV'ing morphine pills. might be something similar somone else can elaborate on.
and the rash like bumps your talking about are fairly common, ive read on this site in several places that its a histamine reaction. first few times it happened to me it scared me really badly, i thought i did something wrong and would have to go to the hospital. depending on the batch of Heroin
i get i get that reaction, its never stopped me from using though. if you take a benadryl
30 minutes+/- before you inject, it should help with that if its a problem for you.