You can use some type of facial astringent, but the best remedy for shave bumps is to give your face a rest from shaving. Continually shaving over the bumps, even lightly, will just further aggitate the skin and will not give your face adequate time to heal

There are several things you can do to prevent them in the first place:
-Don't shave ATG
-Use ultra light pressure when shaving
-It helps to have an optimally shap razor
-Use alum post shave
-Avoid greasy aftershaves/face creams