@sayalip If you have your retainer handy and it hasn't been too long from the completion of your treatment, something as simple as wearing your retainer (if it fits) for 24/7 may lead to some improvement and maybe some slight space closure. If your retainer is loose, you may be able to schedule an retainer visit with your local office and have them adjust it for you. If those options do not work, you can potentially look into invisalign or just limited braces for a short period of time for cosmetic correction. As always, retention is for a lifetime, once spaces are close it is of the utmost importance that you wear your retainer to ensure it doesn't open up again. Good luck with everything.
