Hole in the gum in the molar area is due to infection of the gums or due to infected tooth as it is in relaltion to molars, so may be the molars are decayed and infected causing a gum boil which after draingae looks like hole in the gum. As you are not even brushing and having bad breath, so this gum hole can be because of poor oral hygiene and deposits causing the infection in the gums. You have to visit a dentist and find out the diagnosis and in the meanwhile try to maintain good oral hygiene by brushing twice a day and doing warm saline rinses. for more info on gum diseases you can read this article... http://www.identalhub.com/article_signs-and-symptoms-of-gum-disease-20.aspx