Ok, the really bad consequences of stimulants are when the peak of the drug is in your system--seconds to minutes after intravenous adminstration, minutes to 1 hour otherwise. Most of the serious consequences of stimulants are immediately obvious. So, if someone survived long enough to send this question, most of the serious risks are over. The non-serious side effects often last hours to a few days. These include arm infection, which takes a day to show up and is pretty obvious. Lack of sleep followed by crashing. Mental changes such as agitation, paranoia, anxiety/panic often take days or weeks to disappear. Repeated use makes all of these much worse and brings up entirely new sets of problems that would be rare with ONE use (teeth, heart, skin, weight/muscle, brain damage, etc.).