I have very heavy flow in first two days of the periods. A hot water bag helps to manage the pains. A xxl pad with wide back will be a good option to consider as it's helpful to prevent stains. Check paree ultrathinz, they are xxl with wings, wide back, absorb nicely. It also sticks to the innerwear properly n doesn't move, due to which there are no stains as well. I didn't get rashes too, so a plus from me. Try n see if it helps.