The needles usually are attached to a small machine and tubes that hold the dyes. The tattooist moves the machine over the tattoo area, while the needles pierce the skin and inject the dyes. Depending on the size of the tattoo, it can take up to several hours to apply it. The procedure is somewhat painful, and, like any cut or scrape of the skin, it causes some bleeding and takes time to heal. Non-permanent tattoos can be applied with a brush using a dye such as henna. These wash off in several months.

As in any wound to the skin, a scab forms over the site. Experts say it's important to leave the site alone until completely healed. This will help prevent infection or problems with how the tattoo looks.

Although tattoo shops may be more hygienic than in the past, the procedure still has its risks. One of the main problems linked to tattoos is developing an allergic reaction to the dyes used. The pigments can include metal oxides and synthetic dyes, the FDA says. If the tattooist isn't scrupulous about procedure hygiene, the tattoo site can develop a bacterial infection. Hepatitis B also has been passed on through tattooing. Other diseases that may be passed on through tattooing include Streptococcus pyogenes, hepatitis C, D, and G; HIV; tetanus; tuberculosis, and MRSA. MRSA is a severe staph skin infection. Other complications include nodules that form in the skin around the eyes (granulomas) and scars that grow beyond the tattoo site (keloids).

Experts say that's why it's important to weigh the pros and cons of a tattoo or permanent makeup carefully before going ahead with the procedure.

Laser treatments may be able to lighten a tattoo, but they are expensive and may need several months to complete, the FDA says. The area of skin treated may end up lighter than the surrounding skin, and some people may develop an allergic reaction, because the laser treatments may release allergenic substances in the dyes. Dermabrasion involves removing skin layers with a wire brush or sanding disc. This procedure may leave a scar. Always assume the tattoo will be permanent.

Besides these, the shop should also use a disinfectant or bleach to clean items that cannot be put in the autoclave. The shop should appear clean.

State and local health departments regulate tattoo shops and facilities. You can check out an individual tattooist by seeing if the person is certified by the Alliance of Professional Tattooists.

The most popular site among men for body piercing is the earlobe.

The American Dental Association (ADA) is against any piercing of the mouth—whether tongue, lip, or cheek—because of the risk for broken teeth, difficulty chewing, speech problems, and infection. The American Academy of Dermatology approves piercings only for the earlobe. The earlobe is safe because it is made of fatty tissue and has a good supply of blood.

The jewelry placed in the pierced site should be made of stainless steel, gold, niobium, titanium, or platinum. It should be new - never previously worn or used. A piercing shop should not use a piercing gun for the procedure. Experts say that piercing guns are difficult to sterilize and that they are less precise than other piercing methods.