Instead of trying to dent the lid, you can relieve the inner pressure of any containers like the salsa with metal lids by taking a spoon and sticking it between the lid and bottle to try to pry the side of the lid away from the bottle to create just enough of a gap to equalize the pressure. You don’t need to apply much pressure, you usually hear the pop of the lid when the pressure is equalized and then it should be much easier to open!