If you did a cycle and made really good gains, but did the wrong PCT...
A. will you re-gain back what you lost?
B. Make more gains? when you do another cycle, of higher dose with proper PCT
If you lose from a cycle, you won't magically wake up to find that those gains have returned. If you keep up with proper nutrition and train hard you will still produce gains naturally. So yeah, you could get back to where you were via natural means. Unless you did another cycle to expedite the process.
sorry, made the edit