I did not have the time to play during the solstice event and i still got the drained set and i was wandering if these is or will be a way to get to legendary set or am I gonna regret for the rest life that I did not complete the armor set in time ?
The ability to upgrade the sets is only available within the time frame of the event. Once reaching the legendary armor (purple), Masterworking them could be completed after the event, but upgrading from green to blue and blue to purple had to be done during the event. So, it sounds like you're going to regret it for a while. The event is over, and as such, the armor is no longer upgradable to the next step(s).