It had to mean something besides an allergy to paint. Otherwise it is wasted focus of information given in a movie...This is not done...
SPOILERS!!!
Maybe some kind of symbolism.. Maybe a foreshadowing of the tear seen in his wife's eye at the end of the movie.. And so on...Obviously I don't know but it had to be something...
If his eyes were hurting from the paint he was using on Marie's house, you could argue that it symbolizes the way in which trying to create a new life for himself is causing him pain.