Laser facial resurfacing is used to correct photodamage and improve acne scarring. Methods of assessing the adequacy of treatment and following laser effects over time, however, are lacking. Ultrasound can be used to study skin by virtue of its echogenic and hypoechogenic bands. Of particular interest is the subepidermal low echogenic band (SLEB), which represents water accumulation in the papillary dermis and varies as a function of age. We used ultrasound to study changes in SLEB layer thickness before and after laser treatment. Six patients (four female, two male, average age 54) were treated using the CO₂ laser (Coherent Ultrapulse 5000C^®) for perioral, midface, and glabellar/forehead acne scars or rhytids. Ultrasound (Longport Intl Episcan I100^®) assessments were performed before and immediately after laser and in follow-up 5 days to 4 weeks postoperatively. After controlling for variation in subject and facial region, there was no significant difference in SLEB thickness before (0.31±0.08 mm) and immediately after (0.33±0.09 mm) laser treatment. At follow-up, however, we noted a significant increase in SLEB thickness (0.71±0.23 mm, p<0.0001). In summary, SLEB thickness increases after CO₂ laser treatment of the face and may be a way of following laser effects over time.