Hi, you should have it checked with your doctor it could be lichen sclerosus do you have any on your foreskin and frenulum if it was LS you would need treatment.
As long as you don’t have any symptoms like itching, burning or pain, there isn’t much to worry.
If you are anxious about it, visit a urologist for reassurance.
the photo is not clear but if the texture of discoloration is same to regular skin then there is nothing to worry about