I've had a lump inside my lip for the last 3 weeks. it doesn't hurt if i touch it. photo: http://i.imgur.com/e2gozeb.jpeg?

Fibroma: Could be from trauma or continuous habit of biting your lip. Probably a fibroma. If it bothers you a lot, see and oral surgeo.

Salivary gland: Often this occurs with damage to a minor salivary gland. It should be a clear lesion. The lump is filled with saliva. Often this will go away on its own. Seek treatment if it last more than 2 months, grows in size, affects speaking or chewing or is painful. Google a mucocele for images of this phenomenon.