Kindly lay your complaints/observations at the hospital because they are in a better position to physically evaluate the site. You have the right to ask questions whenever you're in doubt.

The whitish substance you see is called Smegma, which results from secretion of oil glands of the skin as well as dead skin cells .It accumulates under the foreskin. The foreskin should be pulled back gently and washed thoroughly with mild soap and water during a daily bath.This will prevent it building up and possibly getting infected (in which case it,if left untreatd, will become foul smelling and can lead to more serious infections of the penis). Accumulation of smegma is less common or rare in the circumcised. If after attempts at proper hygiene have been made and the accumulation continues, let him be reviewed by a doctor(paediatrician).

Do not attempt opening it by yourself. Kindly see a urologist or a surgeon in a teaching hospital for an assessment of the condition.

Most children will complain of pain or discomfort when they have an erection which is a normal thing in that age group. It usually goes after a few minutes. It is only if the erection or pain is SUSTAINED that you should be concerned or seek medical intervention

Anyway what I think is happening here is what we call Buried penis... that's the prepubic fat hides part of the penis.

Try Tribotan or Cacatin

If he releases into you. Yes, it's possible to get pregnant

Tried Cacatin?