Blackhead and Pustules

Blackhead noun - A black-tipped plug clogging a pore of the skin.

Pustules and blackhead are semantically related in blemishes topic. In some cases you can use "Pustules" instead a noun "Blackhead".

Blackhead and pustules are semantically related in pimple topic. Sometimes you can use "Blackhead" instead a noun "Pustules", if it concerns topics such as small swelling on the skin.