My Son Has Aspergers And He Had Been Take Risperidone

My son has Aspergers and he had been take risperidone for few months.He isn't the type of child to gain weight quickly or easily.So once I notice the weight mass gain he was taken off.He also had stiffness in his body alone with other issues.Hes was on it from August 2014 to May of 2015.But once again another doctor put him back on after I explain the issue for few months and the issues have cause swelling all over.Among personal issue he's says he's having issues urinating because of he's body mass isn't going down.He isn't on any medications could a detox help with decreasing issues?And how long can it take for side effects to stop?