Should i be worried about a tiny bump underneath my skin been there for awhile on my left arm?

Lump: Such a superficial lump sounds benign and may be a lipoma or simple inclusion cyst. However if it's increasing in size or causes discomfort, have your physician examine it and advise you.

An exam would tell: "bumps under the skin are not uncommon and are usually benign, or harmless to your health. most commonly they are a type of cyst or fat deposit (lipoma). If the lump does not change in character or size and is not causing problems like pain you are likely not to fear. If it gets red, warm, painful it represent the bump got infected and a doc would need to see you.