scars and infections
Depends on your body, how old the piercing is, and what size the piercing is.
It depends on how fast your body heals, and how long you have had the piercing. The longer you have had the piercing, the longer it will take to close. This is true for all piercings.
Generally a professional body piercer will discuss this with you before the piercing is done and assist you in selecting the right gauge and long enough to achieve the desired effect from the piercing. Most hoods are done with 14g barbells about 1/2" long or longer depending on the developement of the hood.
any body can get a lip piercing as long if its a unisex or male stud or jewelry
It depends on how long you have had the piercing. if its new about a couple mins to an hour maybe depends on the body part you put the piercing. if you had it for a while it could take a couple days to close or a month
Nerve damage, excessive bleeding due to hitting a vein, blood infection, blood poisoning, Staph infection......... I could go on but I think you get the point here, the human body is not a pin cushion, however when you get a piercing from a professional body piercer you will have a piercing that will heal and look good for a long time without the grief of botching your eyebrow piercing and doing a whole lot more damage than you were counting on. Leave the piercing to the professionals.
Depends on how long you've had it, what gauge it is, and how your body heals.
If the piercing is over a year old you can remove the Monroe piercing for several hours without fear of the piercing healing closed. Prior to a year you are taking a gamble on how your body will respond to the jewellery being out of the piercing.
As long as the body takes to minimize the piercing and close it, there is no magic solution that will make it close faster. It's just a matter of time.
The worst long term effect i suppose would have to be death!
It really depends on the type of piercing and long you've had the piercing.
So long as the piercing is done by a professional body piercer working in a licensed and inspected facility you should have no problems. Piercing guns are not designed to nor intended to be used for nostril piercing, in many countries the use of a piercing gun is strictly governed by local and federal health regulations. Now as for nerve damage, there is a nerve bundle that is not far from the area that is pierced, so care is needed to maintain control of the piercing process. This is why body piercing in any area of the body should always be left to the trained experienced professional body piercers.