What the numbing feels like: anesthesia during Mohs surgery

Mohs surgery is done under local anesthesia, which means only a small area of skin is numbed while you stay fully awake, alert, and comfortable. You are not put to sleep, and for most patients that single fact turns out to be the most reassuring thing about the whole procedure. According to the American College of Mohs Surgery, the technique is performed in the office under local anesthesia, which is part of why it is so safe and why you can go home the same day.

The numbing starts with a quick injection, and the sting is brief. The surgeon injects a local anesthetic, usually lidocaine, often combined with a small amount of epinephrine that narrows nearby blood vessels to limit bleeding and make the numbing last longer. The needle is fine and the injection takes only a few seconds, but that moment is the part patients feel most: a brief sting or pinch, sometimes a mild burning that fades within seconds as the medicine takes effect. After that first stick, the area goes numb and the discomfort is essentially over.

Once the area is numb, you feel pressure but not pain. During the removal of each thin layer, you may notice tugging, pushing, or a sense of movement, and you will hear the ordinary sounds of the instruments, but the sharp sensation of cutting is gone. If you feel anything genuinely sharp at any point, telling the surgeon is exactly the right thing to do, because a little more anesthetic solves it immediately. Patients are often surprised by how little they feel once the initial injection has worn in.

You may be re-numbed between layers, and that is completely normal. Because Mohs removes tissue one layer at a time and then reads the margins under the microscope while you wait, a single tumor can take several rounds. Local anesthesia does wear off over the hours a Mohs day can run, so if the surgeon needs to take another layer, the area is simply topped up first. The repeat injection into already-numb skin is usually far less noticeable than the first one. This rhythm of numb, remove, wait, and check is also why the day runs long.

Staying awake is a feature, not a compromise. Local anesthesia avoids the risks and recovery time that come with general anesthesia and deep sedation, which is one reason Mohs can be done safely in an office setting on patients of almost any age, including many who could not tolerate a larger operation. The Mayo Clinic notes that Mohs is performed under local anesthesia as an outpatient procedure, so there is no breathing tube, no grogginess afterward, and no need to fast beforehand the way general anesthesia requires.

Anxiety is common, and there are gentle ways to manage it. Being awake for a skin surgery makes some people nervous, and that is a fair feeling to raise at the consultation. Simple measures help: eating a normal meal beforehand, bringing music or a book for the waiting stretches, and having a companion along for support. For patients with significant anxiety, some surgeons can prescribe a mild oral sedative to take before the appointment, though most people find they do not need one once they understand how little the procedure actually hurts. A little preparation for the day goes a long way toward calm.

Side effects of the local anesthetic are minor and temporary for most people. The numbness lingers for a few hours after surgery, occasionally causing a temporarily heavy or odd-feeling patch of skin that returns to normal on its own. The epinephrine can cause a brief, harmless racing heartbeat or shakiness in some patients right after the injection, which passes within minutes. True allergy to modern local anesthetics is rare, but the team will ask about prior reactions, so mention any you have had.

The honest bottom line for a nervous patient is that Mohs is far more comfortable than most people expect. The worst of it is a few seconds of stinging at the start of each numbing injection, and everything after that is pressure and waiting rather than pain. Understanding that the long day is mostly sitting comfortably between short, painless bursts of activity is usually enough to replace dread with something closer to boredom, which is exactly the right feeling to have on a Mohs day.

Related reading: How to prepare for your Mohs procedure and Why does Mohs surgery take all day?