What is this itchy bump on/below my eyelid?

I noticed it yesterday morning only because it was itchy in class, then when I got home I realised it was red and there was a bump. It's on my right eye(left side of pic), the lower eye lid on the side closer to my nose-in the pictures it's right where my iris punches my eyelid-it's not very noticeable but it's itchy and there's a bump.
What is it?
What caused it?
What can I do for it?
Can I still wear my contact lenses?
Thanks!
Ps-even if you don't know all the answers, anything helps! :)

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