What is the bubble on the scar tissue?

I do not have your complete history but coughing up blood after a TT is a medical emergency.  It may indicate you have a pulmonary embolism which is very dangerous.  Other potential problems are pneumonia, pneumothorax, fat emboli syndrome.All of these should be evaluated immediately....

This is an unusually large area of full thickness skin loss, rarely seen in cosmetic surgery. The reason is poor vascular flow to this area, whatever the cause. Your surgeon is right, that this large area to be healed in fairly short time (weeks) would require a wound vac system. This means,...

Unfortunately scarring is somewhat unpredictable and it's management can be challenging.  Radiation treatment can be very effective for problematic keloid scarring.  The procedure involves surgical excision followed by three radiation treatments in consecutive days, typically starting...