Soap and water (as warm as you can bear). Good hygiene and patience are all that's needed.

If you lack patience, or if there is a particularly persistent livid rash then see a doctor because you might need medication.

The above applies to acne-type afflictions only. If you have spots over your whole body or inexplicable rashes that don't go away or are accompanied by other feelings of ill-health then I suggest you see the doctor anyway.

try putting a little bit of toothpast on it before you go to bed, then washing it off a few minutes later. it will dry it out and possibly kill some of the bacteria. not particularly scientific, i'm afraid. don't apply much and not anywhere near your eyes! i'm not sure if it will work on acne..

don't overkill though, if you dry out your skin too much then it will produce even more oil in an attempt to compensate. the best thing to do would be to choose one product and stick to it. or possibly a cleanser and a moisturiser.. agree with above although soap will dry your skin out pretty badly

I have used a corn remover successfully.  In the USA we have Dr. Scholl's which is a mild acid in a colloidal solution. Leave it on until it falls off.  Or, scrape it off after a few days and reapply. I think the name of the spot is Hematoma; dried blood.  Spots that are deep won't respond.  Raised ones do go away.