The Gate of Good Fortune the MC loses his cultivation from injury in chapter 85 and heals them in chapter 87. Later on he gets trapped in the forbidden land and his cultivation is sealed in 309. He regains it in 319. Mo Wuji even implied that all he needs is to cultivate with some high grade immortal energy to recover. A few immortal crystals and he'll probably be fine. Heck, the girl he just met is currently offering to help him recover.