Can you be poked by a needle and not notice it?

Very tiny needles may provide almost imperceptible discomfort, especially in patients who have peripheral neuropathy. There are cases of bats carrying rabies, who have bitten unaware patients who later contracted rabies. It is not unusual to be bit by a mosquito and not be aware until later (local numbing). Lots of permutations conceivable.

Many (most?) who ask such questions are worried about being at risk for HIV because of an unknown needle stick. If that's your worry, please don't. It's probably never happened, unless maybe you were unconscious (e.g. from alcohol or drug overdose) when someone injected you with previously used equipment. It that hasn't happened, you have nothing to be worried about. Best wishes.