In my experience, my skin is constantly changing. I started hormones right after my 24th birthday, and have been on them for over 2 years now, and my skin seems softer and silkier almost every month. I guess after about 16 months on hormones, my cheeks and other parts of my body became very smooth and reflective of light. I also use a skin cleaning brush daily called the Clarisonic, which is absolutely amazing if anyone has some extra cash and wants to dramatically improve their skin. I bought one for my mom, and for my sister, and now my whole family and a lot of my friends have them because they are so incredible (especially for taking off makeup).
I also think your skin changes, like most other hormonal changes, vary depending on the age you started hormones. Depending on how much you've aged as the opposite gender, it's going to take longer to reverse those changes. Even though I started hormones at 24, I was at the age development of a guy who was 16 or 17.. in that I could barely grow any facial or body hair. I was so behind in male development that when i moved here and started riding the bus at age 23, the driver would automatically assume I was under 17 and charge me for youth.