Based on your brief history,one differential diagnosis could be a dermoid cyst
.The classical location of a dermoid cyst is just lateral to the eyebrow,which is were you seem to be mentioning the swelling to be.
Dermoid cyst is a benign swelling consisting of mature elements.So the chances of progressing to complications is pretty small.Sometimes it may extend into the deeper layers.It is usually common in younger age groups.
Treatment consists of excising the swelling in total.You can fix up an appointment with an ENT surgeon or a general surgeon
and get it worked up.
All the best.