My 1 year old son accidentally put his foot on a boiling water before taking bath. we're on the third day and he has an open blister, how can i treat open blister on a 1 year old baby?

Clean it/abx: I would clean it often with soap & tepid water. You can apply an over the counter antibiotic cream or ointment. A loose bandage between cleanings covered by a sock can avoid getting it dirty. Be sure to view the area several times a day. If the area has increasing redness or drainage have his doc check it. It will likely heal okay in a week or so.