Hi,
As guiding principle, it is advisable to allow the skin to heal completely or at least significantly after one procedure before undergoing the next procedure.
Q-switched laser treatment is associated with fairly rapid skin recovery. Hence a gap of 4-6 weeks should be adequate before going for a more aggressive treatment such as TCA Cross.
Nevertheless, you should discuss the above with your attending doctor who is the best person to advise you on the proposed treatment protocol.
Hope this helps!
