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Could it be a chalazion? I had a lump in my eyelid a few years ago and that's what it was. That didn't hurt though. Or could it be blepharitis? I get that quite often and it's really sore. I find that taking a zinc supplement really helps.
I wouldn't even bother with a pharmacist.In our area there are opticians who will deal with eye problems. But, if it were me I would ring the surgery and emphasise that this is an EMERGENCY, and don't be fobbed off. Eyes are vital. Do you wear contact lenses?