You can shower the evening of the procedure. I would avoidtaking hot showers or using abrasive cleansing techniques- wash cloths, loofahs,etc. Wash the area with warm water, a gentle cleanser and fingertips, andrinse well and pat dry. You should also avoid shaving until the tenderness has resolved,and avoid using deodorant/antiperspirant for the first few days following theprocedure. Ice packs wrapped in a towel should be applied to the underarmsimmediately following the procedure and on and off for the next several days.
I recommend that you shower no sooner than 24 huors after miraDry. I would rinse the area and not rub too much as it would be sore.