I believe it's safe to laser the scalp, no harm should come to the hair because the grafts are safely in the lower Derma layers.
Dr Bernstein has this on his website;
Lasers use an intense beam of light to gently vaporize skin tissue to improve scars and smooth out the skin. Laser resurfacing can be used to improve the scarred skin that resulted from hair transplants that used larger grafts. Compared to other resurfacing techniques, the laser offers more control in the depth of penetration of the skin s surface, allowing an increased degree of precision and safety. The most advanced lasers use fractional technology to maximize healing after the procedure.
Fractional resurfacing lasers utilize a specific energy to poke tiny holes in the skin surface. This process stimulates the production of new, healthier collagen resulting in smoother skin and improvement of scars. The fractionated nature of the laser means that healthy skin is left in between the treated areas. This allows for faster healing and few adverse effects.
The most effective resurfacing lasers include the Fractional CO2 Laser and the Fraxel Re:store Laser.
- The Fractional CO2 laser is an ablative resurfacing laser, meaning that it uses high energy levels to create tiny perforations in the skin s surface. Only one treatment with the Fractional CO2 laser is generally required.The Fraxel Re:store laser is a fractionated erbium laser; it uses fractionated laser energy to heat tiny columns of the skin, without breaking the skin s surface. There is very little downtime after non-ablative fractional resurfacing, though multiple treatments are required.