Well i am considering the hardness of the pimple as the Nodular pimples which you can feel , so pimples are of different types or stages so some times we can see them on the skin and you dont have to feel them , sometimes we dont see much on the skin but the moment you feel with your hand you fee there is some hard thing so these are called as Nodular Acne . Nodular acne is a time when you have to visit your dermatologist because nodular acne need systemic treatment and wee need to find out the reason , so their could be hormonal acne also so we need to treat everything in total , so Nodular acne treatment of choice oral isotretinoin which is given for 2 to 3 months with gradually reduce dosage , and of course topical face-washes , antibiotic creams and comedolytic cream , retina or retinoid creams in the night time which help the feeling of the super facial of the skin , Reducing oil content in the glands so sometimes we also have to give oral antibiotics and androgens like spironolactone . so for this visiting a dermatologist is very important. This hard pimples which are going to land up in scars which are going to give lot of depressed acne scars which might stay permanently , so we need to treat in a multi pronged approach , so systemic or oral meditation , topical creams and simultaneously treatments like peel , acne laser or Micro needle radio frequency.
source