I'm sorry but generally when you use heat it dilated blood vessels and make the tissues redder. I can't help you with an explanation.
JCH III MD
I know about blepharitis, of course I have looked at the archives and found out everything there is about it... But I can't find any reason for this specifically...
We have discussed Blepharitis at length. Use the search feature, health topics and archives to review the many, many posts on treatment of blepharitis.
JCH II MD