This is on the back of my husband's head. they just showed up about a month or so ago. thinking it's a skin tag but not sure if it's that or warts?

Many possibilities: Did you know there are hundreds of different kinds of skin lesion? Many of them occur on the scalp. Scalp lesions include moles, seborrheic keratoses and other harmless spots. Your doctor should see his doctor if he is concerned, especially if the lesions are increasing in number and size or are causing symptoms

Skin lesion.: Can't see the picture, but lesions like this generally should be evaluated and removed if need be for definitive diagnosis. Skin tag? Wart? Mole? Melanoma? Remember, the head is a fairly sun-exposed part of the body, so skin cancers are possible. Get it checked out locally by a Dermatologist very soon.