I has been 3 years already, this group of hair didnt grow longer. it is not fall or turn grey. It is just still there and not getting longer that that.
It is not ingrown hair, but I dont know what is it? can anyone tell?
There is a lump of something just below those hair. It could be a Lipoma or another type of cyst that’s cutting off the blood/nutrition to those hair.
Go to the dermatologist ,he’ll test you and find out.
Also did you try to pull them out and see how they regrow ?
thank you for your reply.
Yes i have been try, but it is too short to pull out 
that is so annoy me
Ask a friend with a magnifying glass to pull them all out and try to squeeze (the cyst/pimple) and see what happens , sometimes ingrown hair can grow out of control with complications with time .
I’m surprised you let it go for years ,I’m the type of person that runs to the doctor at the first sign of anything unusual.
It looks like a mole or cyst on the scalp. You can try applying honey to it to make it fade away within a few days.