That depends on your skin type and the cause of the blemish. Test it on your arm first before slathering it straight on to your face.

Once I started keeping pure isopropyl alcohol (99.9%) around the house to use in several hobbies, I quickly gained some deep respect for it’s magical properties and it’s ability to dry anything it touches. Diluted or not, I don’t look at the stuff the same way anymore.

(Also of note, rubbing alcohol is isopropyl and aftershave is typically ethanol.)