Thanks for aksing the query,
Drooling of saliva can be due to inability to close the lips completely or difficulty in swallowing excess saliva at night.
There are many factors that contribute to excessive blood tinged saliva at night this can be due to leukemia
, liver diseases, mouth ulcers, oral infections , pericoronitis
due to wisdom tooth, prolonged use of certain medications.
I would suggest you to visit Dentist
and Physician and get the checkup done.
Apso get a Blood investigations done to see whether you are having any blood disorders and Diabetes
Hope this helps out.