Hello, I am currently on suboxone and have messed up left and right, withdrawals from heroin involve sweating, vomiting, nausea etc.. He may not have gotton the 4 suboxone tablets that he said he got, in some places they are worth 10 dollars a pill on the streets,and some get those pills from the doctor with the intentions of selling them for heroin, he may have taken that money(that most likely he borrowed from someone and used getting the subs as an excuse for getting the cash) and purchased a bag of heroin with it instead. Don't forget us addicts will say and do whatever it takes to get that next fix. If he was actually taking the suboxone then he wouldn't have any withdrwal that's the whole purpose of this medication is to prevent it from happening. The only way he would go into immediate withdrawal symptoms is if he had heroin in his system and for some reason tried to shoot up a suboxone this would send him into immediate withdrawal, but he would've had to have done it within hours of using. Most likely though (since suboxone are worth money, I highly doubt that his friend just "gave them to him") he got a bag instead and probably still has a habit, you can tell how big the habit is by how severe his symptoms are. Hope this helps a little. Good Luck. ps keep in mind, he sold his pills so why would someone else just give theirs away!!