Risk of infection is very high when using unregulated devices in an environment that is not clinical or sanitary; it is also very easy to unknowingly roller a part of the face that is already infected. In a clinic, each treatment uses a new, single-use sterile roller per client which is subsequently disposed of, whereas those microneedling at home often reuse rollers multiple times. Using alcohol does disinfect the tool, but it is difficult to sterilize it completely, so not all harmful microorganisms are killed. The needles also become blunt when reused, which severely compromises technique. "Not only can you create bruising and track-mark lines from using too much pressure, but the wrong technique can easily cause micro-tears in the skin, leading to scarring and hyperpigmentation ," Montlake says.