pimple on fyelid

Since it's increasing in size and is in such sensitive place, I think you really will need to see the doctor so you can get the right treatment for this (probably antibiotics). You don't want to risk eye infection and damaging your eyesight, this has been going on for a month and you really can't let it go on much longer. Until you get to the doctors make sure you don't irritate the area even more - no touching or trying to squeeze it. Instead, keep it clean and some cold, clean compress or cloth may help to sooth the pain. But you must have a doctor check it and see what it is.