i thought i'd post this, this is a basic ref of how drach's glowing spots looks in different moods.
neutral: a weak glow which is barely visible at day and a bit visible at night, not too bright.
sad: a very dim glow, sometimes also makes the spots to darken, not visible at day, slightly visible at night.
happy: a slightly bright glow, a bit easy to spot at day, impossible to miss at night
exited: a bright pulsating glow, slightly brighter than when he is happy
angry: a very bright glow, nearly covers the arm and lights up more than a glowstick, easy to spot both in day and night, his eyes as well will glow.
enraged: a very bright glow surrounding his entire arm and lights up alot around him, will also heat the area around him a bit, and you will be able to see an orange glow come through his scales as well as the eyes will glow with the same intensity, if he gets really enraged the glow can turn white out of heat, clearly visible no matter what