Salt and ice challenge is extremely dangerous for skin. Though its a recent fad amongst teenagers it should not be done as it might burn the skin extensively and can lead permanent scars
. You have most probably already burnt your skin. Kindly consult a dermatologist
, so that the extent of your burns can be seen and treatment can be advised to prevent scarring or pigmentation. In the meanwhile use an antibiotic and steroid
cream and a painkiller if required. Clobetasone
is a bit mild for arms. Take care.