Unless the OP can't drive. Thai driving licence entitles you, for a period, to drive in other countries. Its a scam for people who keep failing their own domestic test.
After 48 hours you will know if the antibiotics are working. It's been more that 48 hours now. Sounds like you need the clinic to repack your dressing for travel, and take some pain killers. If you have a worsening ulcer it will take 4-6 weeks to heal. You must travel now, all the moreso because you have CKD and are immunocompromised. CKD is associated with Calciphylaxis, which can cause serious complication. Whether its possible depends on the prognosis of your renal disease. Itis is a ulcerating and painful syndrome that will not respond to antibiotics. Has the doctor confirmed an infection due to raised WBC? Does he understand your health condition. I think you should urgently return to the UK and seek treatment. Call your GP in the UK, or even try 111, as you can speak to a doctor through that. Presumably your travel insurance will pay out on medical evacuation. If you had normal health, after 4 days on antibiotics, inflammation will be markedly reduced. If your room has a bath, spend your time soaking in hot water as this will improve your fitness to travel.
You're posting on Facebook, ergo you haven't got a "bad infection". A "bad infection" will leave you pretty incapacitated. You have a suspected bad infection, a doc has prescribed a broad range antibiotic which should start to show a resolution in the first 24 hours, if not you need to contact the doc for a different prescription. There are going to only two circumstances where an infection might stop you boarding a flight. 1. You have a communicable disease like the Plague, in which case you would be in hospital and be a headline. 2. You have a skin infection that has become cellulitis, and you are obese. Medical opinion is somewhat divided whether you are then at increased risk of a DVT if the wound is on a lower limb. A flight will not impact on the resolution of the infection. I traveled with cellulitis on a leg, there was no issue, I just took some aspirin aa a precautionary measure, under medical supervision. Call your own doctor at home if in doubt.