damon muller has almost doubled in size due to swelling and bloating since he was diagnosed with juvenile dermatomyositis -lrb- jdm -rrb- in november - a rare autoimmune disease that means he ca n't go out in the sun without breaking into a severe rash and his throat can swell so much it almost closes over .
damon muller has almost doubled in size ... he has gone from an active kid to barely being able to move in just five months .