Hi there! I also have some favorite articles about it
https://www.mayoclinic.org/diseases-conditions/ingrown-hair/symptoms-causes/syc-20373893
It is said that you should use a sharp razor (like Braun). With a dull razor, you’ll likely have to go over the skin multiple times, raising your risk of cutting yourself, irritating your skin, and, possibly, getting an ingrown hair or infection. Your razor will typically feel less effective after a few uses, in which case it’s time to toss it or swap out the blades.