Should I do a 3rd session FUE hair transplant? (Photo)

Based on your description you really need to wait for the 2nd transplant to grow in and then reacess your situation.

If you are considering another surgery it would be best to discuss your options with a doctor.  You need to explain to your doctor your goals and expectations. The doctor needs to examine you to give you a better assessment of your donor area.

Most, if not all of the hair that is visible is from the 1st FUE procedure.  Your second surgery was a little under the 3 months it takes to start seeing growth.  I would wait until at least 6 months post 2nd surgery, then see your doctor if you aren't satisfied.  Keep in mind that each surgery takes between 12 to 14 months to achieve full results from that surgery.  A 3rd surgery shouldn't be considered until at least June 2019.  1 year from second FUE procedure.

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. Final result and canopy effect of hair transplant related with caliber of your native hair in donor area; characteristic of hair (waviness or straight hair) ; surface and density of donor area that directly affects the number of harvested grafts; color difference between hair and skin and finally hair style.  If you  are not satisfy with  result of your first operation, would better to check those parameters and think about to plan a second HT to increase the density .

Hard to assess your results thus far without photos from before your first procedure.  At three months the grafts from your second procedure are just beginning to grow; it will be another 5-9 months before you see your final results.  I would suggest you wait at least that long before considering a third procedure.

It is not a good idea to think about third hair transplant procedure this early. You need to wait until all of your hair grows out to see where the transplanted hairs are located. You need to be patient and wait at least a year. Also with multiple FUE procedures there is possibility of donor depletion. You meed to doscuss that with your hair transplant specialist. 

The transplant results either reflect a poor result from your previous FUE or an inadequate number of grafts. Please remember that there is a limit for the number of FUE grafts that can be removed, see below