Golden Severum With Swollen Sore Lip

[Tinks75]

Hi can anyone help my golden severum 8" has a sore swollen top lip, this fish has lived happily with my chiclids in 4ft by 2ft bow fronted tank for over 12 mths with no problems, can anyone help as I love this fish and dint want it to get any worse

 

[Tinks75]

Forgot to add that he is eating well and does not seem to be bothered by the sore lip, I have a photo but unsure of how to upload