Tweezing the eyebrow can be painful sometimes,especially if the root of the hair is thick and strong.
There are several things you can do to prevent pain and red marks from the irritation.
1.Tweeze your eyebrows right after taking a warm/hot shower.Your pores open up with the heat and steam and open pores will release the hair better than closed pores.
2.Apply a nice amount of a thick moisturizer on your brows,that will soften the skin.
3.If you experience a lot of pain you can numb the skin with ice cubes,but be careful,never leave the bare ice cube to have skin contact for more than 15 seconds.This will also minimize the irritation.