You should be aware of the basics of the laser treatment and how to deal with it. Each laser pulse usually seems just like a slight sting. It gives a pinching feel, somewhat similar to the sudden snapping motion of a rubber band. To reduce whatever little pain that might be felt, topical anesthetics are used in some cases. However, a majority of patients do not really need it.
Mostly, there are no major or lasting side effects. In fact, the biggest advantage of the laser surgery is that it rarely has side effects. You might notice some light reddening or slight local swelling around the body part that undergoes laser treatment. However, it goes away on its own within a matter of few hours.
On a few occasions, a little bit of blistering or bruising might be seen. Even that is nothing to worry about as it quickly resolves without any medical intervention. In some cases, the skin may get darker or lighter, depending on its complexion, post-treatment. You should ignore such changes as the skin will return to normal generally within a couple of weeks.
However, you should take the necessary precautions as suggested by doctors. It is important that you carefully follow their instructions and listen to their advice. For example, limiting exposure to sun and protecting the body part before and after the laser treatment will reduce risks, avoid complications and increase the chances of hundred per cent success.