What kind of acne is this? (Photo)

I've had this dark spot on my forehead for probably 2-3 years. It's like a scab. Except that, every time I rip it out ( my skin ) , it grows back. I've ripped it out a multiple times already. But it just grows back. I don't know if this is a thing I have to go to the doctors to get treatment done or its just something I could do like using lime ( I read it online ) . Please help! P.S: please find a home remedy for this!

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