I had 3500 grafts 3 months ago, why is my donor area soo thin? (photo)

The donor area has been significantly impacted by the FUE suggesting that your original donor density was significantly less than what the number of FUE grafts could have supported. Your doctor should have measured your donor area density prior to doing FUE. The limits on FUE is related to your donor density otherwise it produces significant scarring as this photo shows. If the donor area remains see-through, you should get Scalp Micropigmentation to fill=in the missing spaces.