It sounds like you are one of the many women who experience irritation of the vulva and/or buttocks from menstrual pads. Since pads are made up of many layers of different materials including adhesive (glue on the bottom of the pad that allows it to stick to underwear), it’s not unusual to have a skin reaction (often referred to as “contact dermatitis”) to one of these materials. This is especially true if you have sensitive skin. Friction from the pad (moving back and forth) while you are walking, running or playing sports, also contributes to irritation.
You may wish to consider using: a different brand of pad such as an organic “unscented” kind, or tampons, a menstrual cup or period underwear instead of your current brand of pads. You may find relief from irritation by soaking in a warm tub for about 20 minutes. Most of the time, discomfort associated with irritation improves in 2-3 days. If it doesn’t seem to get better, make an appointment with your health care provider. Your HCP may prescribe a topical cream (medicine) to help with the healing process.