Suggest Treatment For Black Eye

Good Evening Doctor Meyer,

I was headbutted in the face, contact was made right in my eye to be exact. Most of the bruising went away, which was very very bad initially, however, it's been 4 weeks now and the black eye hasn't completely gone, it's like I have a permanent skin discolouration under the eye. It's slightly darker than the rest of my face. I'm worried it won't go away is there anything I can do so the colour will be back to normal?

Thanks