Ballet under arm shaving?

i have just started ballet again, i do shows and that as well and when we did our last concert i noticed when i shave compared to everyone else who's armpits look like there never was hair there before mine have like darker coloring under the skin. and its hart to shave every bit off even if i do shave different directions, i will feel really self conscious please help.i know theres waxing but then thats waiting for it to grow each time, really hygienic and i just don't feel comfy please help x