Have Dark Itchy Bumps Under Arms. Always Sweat. Use Deo. On Moisturizer, It Helps. When Stopped, Reappears. Treatment?

Hi Doctor, I have Dark-Bumps-sometimes itchy on my ua. -it always sweat -i use dove deo, because this is the only one that suits me well and the sweatness stop. lessen the itchy too....
My derma before recommended me moisturizer, it really works, my bumps are gone. but when i stop the medicine, it appears again....The medicine is so expensive doctor...What moisturizer cream can lessen my bumps? and less expensive? thank you for reading this letter.