asthma inhaler, it's a steroid that makes the muscles in your airway/lungs expand. you're only supposed to take 2 puffs every 6 hours, if OP isn't lying he'll probably have a heart attack because one of the side-effects is raising your heartrate.
sometimes when you're not having an asthma attack but you coughing or just feeling congested it feels good to take a puff because it makes breathing much easier but it doesn't get you high like opiates do. no idea why OP did this unless he's trying to kill himself, or he's a lying faggot who made this up (probably the latter).