What is the permissible limit for removing eyebrow hair if it is thick and causes a blemish, and what is the criterion for the word "blemish"?

The Shari'ah does not specify the disfigurement or defect that permits the removal of eyebrow hair. This matter is referred to common practice (urf), because whatever the Shari'ah does not define is referred to common practice. The permissible amount to remove is that which eliminates the disfigurement and restores the eyebrow hair to its natural state, because what is permitted due to necessity or need is estimated according to its extent.