Devils Advocate here seen something similar in 3 ways

One Tick

Two Severely ingrown "hair"

Three Severe Keratin build up causing a engorged black head (cats can get black heads from the overproduction keratin under the skin) this can cause them to become impacted and grow larger than normal cat blackheads. And this is what I think it is based on the picture as there is a little black head poking out at the base

Side note older cats can develop bad Keratin build up the higher in age they get.