Out-Of-Network for a Pre-existing Condition, What do I Do?

My daughter has Obama care. She is 27. At the age of 18 she had an operation by specialists in Massachusetts (her Rhode Island doctor referred us as he couldn’t do the operation and the doctors at Hasbro were not helpful in assisting him). She was referred to Dr K the surgeon and Dr P the Infectious disease doctor). They removed part of her jaw (she has Osteomyalitis) and replaced it with metal. She was supposed to have it removed within the year, but since she turned 19 she was no longer eligible for the state aid which we had. A few weeks ago she suffered pain from the jaw. She went to her RI doctor who said it was still in place but needs to be removed as soon as possible. He cannot perform this operation and suggested she return to Dr K so he can finish the job. Dr K is setting up an appointment for her to see him. So my question is how does my daughter go about applying her Obamacare in Massachusetts, since she is from Rhode Island. Thank you for your prompt response.