If it's that bad then it's best to see a dermatologist instead of wasting time with routine cleansing and home-remedies. Acne has to be treated from within before u attempt to lighten the scarring. U can't work on the scars untill and unless u're acne has been treated.. doing that will make u're skin very uneven.
U're derm would prolly give u oral medicines as well as ointments/gels to put on u're face. Everyone has diff skin and so u have to have it shown and get a prescription meant for u're type of skin and condition.