You may be describing Fordyce spots, which are basically prominent sebaceous (oil-producing) glands that require no treatment (although they can be removed for cosmetic reasons via electrodessication or vaporizing laser treatment). Such spots are usually asymptomatic, but may become irritated, especially with constant physical contact (e.g., chewing, rubbing) or inappropriate attempts to remove them. Seborrheic dermatitis (inflammation of the oil-producing areas of the skin) of the lips could also be the cause (usually flares in winter, not the warmer months).
If the numbness or itching or burning sensation persists or worsens, then this could be a sign of an infection (e.g., cold sore virus, bacterial infection) or other condition that should be evaluated by your primary care doctor or a dermatologist (skin specialist).
Fordyce spots reference: http://dermnetnz.org/acne/fordyce.html