hi, i ve been having these swelling little lines and clusters on my inner arms, stomach , lower back and i ve also been itching all around my body. the bumps appear in clusters, are red, and itch. the bumps on my lower back healed and have left dark discoloration in the form of the clusters. the itching is also on my scalp and gets worse at night. is this a type of rash , skin infestation, or something else?