Need some advice

I am a caregiver for a paraplegic who has recently had a flap done on his left ishium. He had the KCI vac before the surgery to try to heal the ulcer, but eventually had to have the flap done. He developed a tear in his suitures right at the bottom of the flap which is lower portion of his cheek. The doc decided to put the vac back in instead of sewing back up. There is so much drainage from the site that I am having a hard time keeping the seal and I am at a loss. I have done the vac at the site of the tear and also done bridges, but still have the same problem. I am not a doctor, but the area looks good and the skin is healthy; I just dont want it to go bad. Any ideas as to what else I can use or ask the doctor that I can use to help keep the vac sealed?

Thanks