Or maybe you forget to turn off the electricity while installing a lamp? Experts say it pays to know how to act in DIY emergencies.

With countless YouTube videos walking DIY enthusiasts through increasingly complex home improvement jobs, home improvement has never seemed easier (or cheaper).

But an overconfidence in abilities can easily lead to painful accidents during odd jobs at home. Poor planning, rushed jobs and using the wrong tools are common risk factors, says Susanne Woelk of Germany’s Safe Home campaign.

That’s why it’s essential to know how to respond to the most common DIY accidents:

Slipped hammer: Many a child can remember the sound of a hammering, followed by their father’s voice cursing loudly. A split second of lapsed concentration is all it takes for a DIY fan to miss the nail and hit their own finger instead.

If it happens, the first thing to do is cool your finger. If it doesn’t feel broken, wait an hour or two, says Professor Florian Gebhard, chairman of the German Society for Casualty Surgery.

Should the pain persist or even increase over time, consult a doctor. “That can indicate a broken phalanx,” the expert notes. Blood under the nails often needs to be let out with a needle.

Electric shock: It’s easy enough to forget to turn off the electricity while working on installing a lamp.

In such cases, electrical wires will send a current into your hands, flowing through your body down to your feet, before it leaves. That means it also flows through your heart.

“It can therefore lead to dangerous arrhythmia, though not necessarily,” says Heribert Brueck, spokesman for the German Association of Registered Cardiologists.

If you feel faint or dizzy or if a dark spot appears in your vision, you should check with a doctor. If you feel very sick or lose consciousness, you should immediately call an emergency doctor.

Cuts: Blood pours out of a deep cut. You were cutting cardboard a second ago. Now you’re clenching your index finger.

Injuries like these can be particularly critical when they are on your hands or feet, Gebhard says. These body parts have many nerves and tendons in very little space, making it is easy to slice one of them.

You should keep an eye on the area around the wound even after the bleeding stops. If you cut your finger and it feels tingly or asleep, that’s a warning sign. “You may have hurt a nerve,” the expert notes.

Surface wounds in areas with more fatty tissue and fewer nerves and tendons, like the thigh, are usually less critical.

A sawn-off finger: When it comes to working with a saw, routine can be fatal. After the twentieth log, you might find yourself losing concentration. But before you notice you need a break, the tip of your finger is gone.

It’s essential to act fast. Stop the bleeding in the stump with a pressure bandage. Dry the detached portion of the finger and put it in a plastic bag. Then put that bag inside another one filled with cold water and a little bit of ice, Gebhard explains.

Never put the cut-off portion of the finger in direct contact with ice. “The cells could freeze, and then the finger would be dead,” the expert says.

Bruising: You are piling up bricks, one after the other. You have almost finished. But the last brick falls on your arm from a height of over one metre. The spot it hits immediately swells.

As with sports injuries, you should apply the so-called RICE technique, Brueck notes: Rest, Ice, Compress and, if necessary, Elevate.

If the swelling is superficial and clearly visible, it’s probably harmless. With deeper swelling that presses into the muscles, bruises can lead to compartment syndrome. Muscles may get an insufficient supply of blood, which can cause paralysis in severe cases.

Swelling in the chest and abdominal areas can also cause damage to the surrounding organs. You should consult a doctor if the pain persists after two days.