I don't know if this is something to be concerned about, so I'm coming here before consulting a doctor about something that is no big deal (aka, a cyst).
I'm 20 years old (almost 21) and have noticed a rather large lump on the right side of the back of my scalp. It spans from right behind the top of my ear down to right where my neck begins, and is about the width of a ping-pong ball at the widest part (it isn't really a specific shape). It doesn't hurt unless I press on it.
Also, I have noticed a rash developing on my left arm. I have a history of eczema, so I don't know if this is related or not.
At any rate, I'm just wondering if this is something I should see a doctor about, or if I'm just overreacting. I don't have any other symptoms as of now. Thank you!