My father is over weight man but he has never had a sore like this before, its right under his arm roll kind of and its like red in some places it looks wet and it smells a bit... any ideas?

Is the sore in an area where skin might rub together or on clothing?

Yes its in like the crease of his role but it's a large area.

Could be a bed sore- a type of ulscer. They're common in bed ridden and overweight people and can be stopped by moving the person every so often or releaving the pressure caused by the fat rolls by moving the arm in a different position every so often.

You can help by cleaning it then applying a topical antestetic like neosporin and then covering it with gause or something similar. Make sure you get him moving his arm so that the sore dosen't have too much pressure on it because these are also called pressure sores (caused by pressure).

If it gets worse, or if you already think it's infected take him to see a doctor as it could cause serious health problems if not treated correctly.

Hope he feels better!

Sounds like it could possibly be a pressure ulcer to me. He should have this looked at by his doctor as infection is highly possible.

I have eight pressure sores, my skin is dissolving; they are similar to your father's sore or perhaps the same. I am being treated by a visiting nurse in my home. I have severe depression, and I don't take care of myself properly, well, at all.

Treatment is thorough cleansing every day with soap(get rid of the bacteria and odor), dry completely, then apply prescribed ointment and keep dry during the day.

Good Luck!