I have a white undereye bump?

If your description is anything to go by, I think that you have something called a stye. As you say, these appear on the lashline just above or underneath the lashes, both on the upper and lower eyelids. They are usually caused by bacterial infections, either from contact lenses, rubbing your eyes with dirty hands, or makeup. Don't squeeze or scratch these eyelid bumps! Applying a warm compress using a cotton pad with heated water, with chamomile tea for instance, can help speed up healing. They will go away by themselves in a few days, but I know they can be very irritating!

Yep, that absolutely sounds like a stye, "an inflamed swelling on the edge of an eyelid", I agree. They are caused by infections, and while having one once in a while is not a big deal at all, developing them regularly should have you wonder what about your eye hygiene you could improve. Using contact lenses for longer periods than you should or not cleansing them properly can, for instance, be culprits. 

If your bump is further away from the lash line it could also be milia or chalazia. Google those to be sure. If they persist, see a doctor, but if not, just take care not to touch the area with unwashed hands and do not pop it. You should be rid of the bump soon enough.

Ah, that's what those are called? Styes? I know EXACTLY what you are talking about and have gotten them on and off for years, maybe twice a year I'd roughly guesstimate. Actually since I started being more responsible about taking makeup off at night they've not really popped up any more come to think of it... could be a link there? I didn't know they were bacterial though and thought they were basically just "eye pimples" if you like. I have to admit I have popped them with my nails before. They are really, really annoying! But yeah of course that isn't advisable. 

Poor hand hygiene followed by rubbing your eyes can definitely lead to a stye, but that isn't the only thing that can cause them. As far as I heard, as someone who gets them sometimes, they are essentially an inflammatory response and you can be excessively prone to them. Folliculitis, which is an inflammation of one of the follicles of your lashes, can also be the cause, and that can simply be caused by something as benign as a mascara that doesn't agree with you. It doesn't necessarily have to be bad hygiene, though we all sometimes rub our eyes with unwashed hands.

First of all, I am sorry. That must be a rather unpleasant experience for you. I can imagine being really bothered by pimples on my eyelid myself. Thankfully I have never experienced it myself. For you though, to start off with personal hygiene is very important. Wash your hands after you have been to the bathroom or gardening or whatever, because I imagine you are tempted to touch it a lot when it is so irritating for you. I would stick to soap and water because those hand sanitizers have alcohol which would irritate your eyes further. Meanwhile how about use artificial tears? That might make you a little more comfortable. Of course if this is an ongoing problem you might need some antibiotic cream for in your eyes but you need to go and see your doctor to get those. Mind you, could it also be you sleep in a drafty spot of the house? You could try to look into that.

I used to get styes constantly as well, and I'm not sure why. I do wear lenses and was of course told to disinfect them and their box properly, as well as to not use them longer than directed, when I went to see my doctor about yet another stye. He also said to faithfully remove my makeup at night, which, ahem, I might honestly not have been all that careful about. I used antibiotic ointment on them when I got them. Weirdly enough, I've now not had a single stye in longer than I can remember, probably a few years now. Yes, I'm very strict about taking off my makeup at night now!

I am wondering what the data is on stye prevalence among lens wearers as opposed to people who wear only glasses or have good eyesight. My theory is that a lot of them, perhaps even the majority, are caused by improper lens care. I know how tempting it is to not clean your lenses properly, not replace the fluid in their storage container, or to wear them beyond their expiry date (from opening them), but styes are only a warning sign. Real eye infections and even blindness can follow. This is why I have decided not to worry any more and only use daily lenses, which are just cleanest and most practical.