No Ryn, you don't need to do anything to it.

When they're newborn the foreskin is bonded to the penis like your nails are bonded to your nailbeds. Over time (from the opening back) it starts to slowly loosen. The general rule is that most boys can retract their foreskin by age 4-5, and if not they need a quick trip to the GP to ensure all is well (which it almost certainly will be, the majority of those boys will be able to retract by puberty, which is when it actually starts to matter) but as you've seen with DS some can do so way earlier.

Until puberty the penis produces minimal amounts of smegma to keep the glans clean and moisturised. Gently clean off any which appears at the opening of the foeskin when it is not retracted. Don't wash the glans (although if DS pulls the foreskin back in the bath, this isn't a cause for worry or anything, it's just not something you need to be doing yourself) and don't retract the foreskin yourself. If you notice infection (redness, heat, "angry" looking opening to the foreskin, more than usual discharge or smegma or pus, fever, signs of pain in the genital region) just take him to the GP.

Regard what is under the foreskin as the same as what is under the clitoral hood of a baby girl - fine doing its own thing until it's owner is big enough to deal with it.

HTH

Bx