
I too think she has to go back to the vets , I had a dog have similar , her wound just wouldn't heal and and was gaping , I took her back to the vets twice and raised this concern about being allergic to the stitches , I was almost laughed at ( but I know I was right !!!!! ) and told to keep on with AB's
When I got home I took the last supposedly dissolving stitch out myself ( I know you probably shouldn't , but I've done this before so knew what to do ) and bathed every 2 - 3 hours with epsom salts , the oozing puss and redness was cleared in a couple of days and the scar healed lovely in no time .
I swear by epsom salts , however I always dab the wound with clear cooled boiled water after bathing so it doesn't sting the dog too much. Could you maybe persuade your customer to bathe the would frequently.