What Causes Mild Headaches With A Pimple On The Hairline?

Hello doctor. i'm 18 yars old and for about the past 4 days I've been waking up with mild headaches. I've noticed if i raise my eyebrows it hurts more. After i noticed that i found i had a pimple right at my hairline. whenever i touch this it sends pain through the whole left side of my head, trailing down my back left side of my skull all the way down my jaw. the pimple doesn't seem to be one really, since it's only filled with blood. please doctor, is this just a pimple or something else?