What Causes Frequently Occurring Red Painful Blisters On Pubic Hair Area?

I have a dark red blister type thing in my pubic hair area. One or two pop up every month and look like blood blisters. When they pop, there is a little white, wax like discharge (like from a pimple) and then it bleeds a lot. It is slightly painful. I am overweight and they appear where my skin fold together. I wear jeans a lot and they can be tight in the crotch area. Do I need to be worried?