Believe it or not, there is a syndrome called feline acne. Like human acne, it is frustrating to treat, and it is mostly a cosmetic problem. Fortunately for cats, feline acne usually does not adversely affect the cat’s self esteem.
However, the growth on your cat’s head does not sound like feline acne. Feline acne usually manifests as scabs and pimples on the chin, not as a solitary growth.
There are many syndromes that can cause a dark masse to appear on the head or face of a cat. Some are very minor. For instance, in young cats the immune system may become transiently hyperactive. This can cause skin blemishes to develop. These blemishes are similar to pimples or blackheads (although technically, they are different), and they tend to resolve on their own over time.
As well, cysts, bacterial infections, fungal infections, tumors, traumatic wounds and abscesses may cause growths or bumps similar to the one you describe. Because cats groom themselves so well, they very rarely are infested with ticks.
The bottom line is that you should have a vet look at the spot. Since the area is sensitive, I recommend that you have it checked sooner, rather than later. The vet will be able to determine whether the mass needs to be treated with medicine, removed, or allowed to resolve on its own.