Swollen eyelid what is it and how to treat?

[Spottyhands]

I'm abroad and my eyelid has swollen up and is quite painful. I feel miserable and I'm not sure from Dr Google if it needs treating.

Any idea what this is? Hopefully I've managed to attach a picture

Yeah I'm already worried as don't trust what I've been told. I can't believe an allergic reaction would last 4 days and get slowly and progressively worse. Going to carry on with the drops today then maybe see about an eye specialist tomorrow. I'd quite like to just come home and get seen in our city's wonderful eye hospital.