FUE Post-op: why does my hair look thin compared to my normal hair? (Photos)

It is important to understand that hair transplant surgery does not replace all the lost hairs.  You need to have clear goals that are realistic.  You may want to discuss your concerns with your doctor.

Thank you for your question. The appearance of thin hair in the recipient area 25 days after procedures is normal. It can take several hair growth cycles to see the results of a hair transplant. Allow 4-6 months to see the first signs of new growth, and up to 18 months to see the full results of your procedure. 
You may want to schedule a follow-up with your surgeon to discuss when the right time would be to resume a hair loss medication regimen. In the meantime, I have included a link below with more details on what to expect after a hair transplant. 

One month post-op is too early to begin judging density. Most hairline transplants begin growing around the third month, and the transplant usually is mostly grown out by the six month. Lots of time before the full effect can be judged.

First regrowth should be observed on 3-3.5 months. Regrowing hair is thin, undersized and not bright untill 4-5 th months of hair transplant. İt's normal for new growing hair starting to get native characteristics, waviness, curl in first 6-7 months..This actually takes 10-13 months for hair to become full mature , as thick and bright  as native hair. 

Thank you for your question and sharing your pictures. At 25 days post op your are nowhere close to your final result. Your transplanted hair must be falling and the follicles are in their resting phase. You will see new hair popping out after 3 months of your hair transplant. The look that you have today is normal.