Hi, Thank you for posting your question here, I will try to answer it to the best of my abilities. The medical term for lung scarring is pulmonary fibrosis. Sadly there is no treatment for it, the only known solution is a lung transplant, which in your case is just plain useless. In some cases corticosteeriods such as prednisone have proven to be helpful, so you could look at that option. But I think a better option for you would be endurance training, to help you get used the amount of oxygen your lungs can provide and breathing techniques to improve lung efficiency. Another option, is for you to carry a small can of oxygen with you when you go hiking, it can provide you with oxygen therapy whenever you feel shortness of breath. I would advice you to not overdo your hiking as well, but since you enjoy it so much I dont think you will listen to that bit of advice, cant really blame you for that. So try the other options I have mentioned, hopefully they will do you some good. Hope you can continue hiking.