It is widely suspected that the anaerobic bacterial species Propionibacterium acnes ( P. acnes ) contributes to the development of acne, but its exact role is not well understood.  There are specific sub-strains of P. acnes associated with normal skin, and moderate or severe inflammatory acne.  It is unclear whether these undesirable strains evolve on-site or are acquired, or possibly both depending on the person. These strains have the capability of changing, perpetuating, or adapting to the abnormal cycle of inflammation, oil production, and inadequate sloughing of dead skin cells from acne pores. Infection with the parasitic mite Demodex is associated with the development of acne.   It is unclear whether eradication of the mite improves acne. 
I have personally verified three on the many claims made by John Armstrong regarding the healing properties of your own urine in his book The Water of Life. I have confirmed that urine makes an great wound dressing, that at least some types of wounds ( cut from knife ) do heal without scaring, and that skin treated with urine over a period of days turns very soft, like a newborn babies butt. See my book review on Amazon if you are curious. Whether established scare tissue can be effected is unknown, but you could give it try. Its a matter of keeping something like a cotton warp moist with fresh urine, and sealed and kept in place. For a wound on the end of a finger, I cut the finger off the end of a cotton glove, put it over the wound, moistened it with my fresh urine, and then slipped a finger from a latex exam glove over the finger to keep it from drying out.