This is a story probably from late 80s early 90s (definitely no later than the mid 90s) where there is a little boy who explores the woods with his dog (scottish terrier?) with a flashlight and I remember the illustrations having a lot of dark colors with him returning to his well lit and warm home
Sounds like Henry the Explorer by Mark Taylor, illustrated by Graham Booth There are several books about Henry and his dog.
It’s possible that this could be one of the Henry books, by Mark Taylor. Henry Explores the Mountains is my guess, because I think that’s the one where Henry gets lost and has a flashlight. There’s also Henry the Castaway and Henry the Explorer.