Why not create a painless hypodermic needle?
The needle will have a jagged outer surface, much like the outer surface of the proboscis of the mosquito. The jagged surface will allow only a small amount of the surface to contact the nerves in the skin, creating a minimum amount of discomfort. Once the jagged sheath of the needle penetrates the skin, a smooth tube will move through the sheath, delivering drugs or taking blood.
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