I'm not sure it is something to be concerned about unless it appears to have 'fluid' inside or if it is painful or feels 'itchy'.
I would suggest keeping a watch on this area and if it changes shape or changes in any way then you may need to see your doctor or a dermatologist.
It looks like a scar from either a paper cut or knife cut, or even a fairly bad scratch. Have any of these things happened in the last few months? If so, you've answered your own question. Just keep an eye on it, and if you see any swelling or redness, see your doctor.
I imagine this is a shallow scar -- maybe a burn so quick you failed to notice. Probably will disappear in a month! Please let us know.
It looks like a scar to me. Did you cut your finger in the past?