Is it soft or hard?
Does it feel like it has fluid in it, does it hurt her to touch it?
Any signs of sneezing, runny nose, etc?
Could be a cyst, abscess, insect bite or pecking injury.
Since it is so close to the eye you might want to use some Vetericyn eye gel or Terramycin eye ointment on it to see if that helps.
Looks like a cyst or blister kind of thing from an injury.
The eye looks good.. so no need to add eye drops.
These kind of things usually get bigger, then burst and heal up fine. Or they get hard and drop off in the end.. but can take some time.
If it gets worse or If you are worried take her to a vet to have a drained.