My DS2 (ASD mild LDs, and hypotonia) has always seemed to have very little awareness of pain.. he doesn't register feeling unwell until his temperature is through the roof, or he is hospitalised! He doesn't notice blisters if his AFOs rub, and last year he had a pilinoidal cyst and didn't tell us until it was horrendous :( I had been letting him shower by himself so didn't see it.
Last week we were both stung by jellyfish on holiday. It was excrucuiating.. I've never felt anything like it. He said 'ow my arm stings' while I (and others in the sea..a clutch of them had suddenly washed in) ran screaming to the life guards for treatment!
Obviously in this instance it was a bonus for him... but it worries me for his future. He is 17 and we hope will live in supported living one day, but how can he be safe, if he can't notice pain, or illness, or that he needs attention?