"There are many different causes for red bumps after shaving. Any reason for inflammation, irritation, infection or trauma (small cuts or razor burn) to the hair follicles will result in red bumps, including ingrown hairs. To prevent their formation, make sure that you shave with a sharp razor and use a good shaving gel or cream. Shave only when you are warm and do not have goose bumps, as they are easy to cut. Do not rush your shaving and do it carefully.
"If you are prone to ingrowns, shave with the grain of the hairs and not against, use a single blade rather than a double or triple, lather with shaving gel in a circular motion to dislodge any ingrowns, and consider depilatory creams or laser hair removal. Do not apply irritating or fragrant creams right after shaving, which may irritate your skin and hair follicles. If you see pus bumps or your problems persist, see your doctor."