What should I do about acne that is hard and festering deep inside and cannot be squeezed?

I thought my skin had calmed down for a while, but now acne is popping up on my chin again. I always seem to get pimples on my chin that can't be squeezed.

If the pus comes up on the surface, I can just squeeze it out, but I don't know what to do about acne that is festering deep inside like a lump.

If I just leave it alone, thinking that time is the answer, sometimes it takes nearly a month for it to heal and the traces to disappear.

Is there any treatment that can prevent this kind of acne? What do people like me who get large pimples that won't pop and fester inside?

Please let me know if you have any treatments you would recommend or home care methods that you found effective.