What is this lump on my finger? (With pic)

[avocadochocolate]

This lump has appeared in last few days. It's not sore or itchy in any way. It's hard. Skin slightly reddened.

Anyone?

Could be a cyst
Could be an infection
Maybe you’ve knocked it and it’s caused swelling and inflammation
I’d give it another couple of days and if it doesn’t get smaller, see your doctor

Thanks @rubyismyworld. I asked a pharmacist today and her suggestion was to moisturise and use a hot compress but she wasn't sure what it was.