A method includes hydraulically fracturing a subterranean formation with a first treatment fluid and allowing the hydraulic fracture to close. The method includes preparing a second treatment fluid having a damage removal agent including carbon dioxide. The second treatment fluid further includes a proppant pack damage removal agent including an oxidizer, a radical initiator, an acid, a solvent, and/or other damage removal agents. The method further includes injecting the second treatment fluid into the subterranean formation at a downhole pressure below a fracturing pressure for the subterranean formation. The method includes holding pressure on the formation while the second treatment fluid enhances formation and proppant pack permeability, and flowing the second treatment fluid back to the surface.