Depending on how soon after labiaplasty surgery your next period occurs, I generally ask my patients to avoid tampons for two menstrual cycles, which allows a bare minimum of about 5 weeks (or up to 7 weeks) for healing to occur.
All scar tissue softening and sensory nerve healing can take 6-12 months or more, but most activities, including intimate ones, are resumed by 6 weeks post op. Tampons are actually not immediately adjacent to the suture lines with labiaplasty, so careful insertion and frequent exchange is possible sooner than this specific recommendation, but I would recommend asking your surgeon first. Best wishes! Dr. Tholen
Web reference: http://www.mpsmn.com/dr-tholen