any kind of weird, spasmodic-like muscle activity after using cocaine is possibly indicative of a larger issue (ie damage of some sort caused by the coke or whatever else was in the coke)....on the other hand, it could be a mild side effect that will resolve without sequela and you should just try to get down a benzo or two and relax. i'm no doctor, though - just a regular old damn drug addict whose only medical training regarding psychoactives and their use and abuse is through more than a decade of daily immersion training and hands-on learning - but for me, anyway, the usual rule is that if it doesn't go away, it doesn't start to get better after a reasonable amount of time and if i'm having difficulty breathing, staying concious, etc, etc....
anyway, good luck with that. keep us posted