Have any doctors used saline injections on patients to repair damage from Hyaluronidase? What are your thoughts?

Intralesional saline injections have been used successfully for treating skin atrophy due to the use of intralesional steroids, such as intralesional triamcinolone. They are believed to work by helping to dissolve and dilute crystals of steroid that may be persist at the injection site and which may be contributing to the persistence of the skin depression. I personally have used saline for this purpose with good success. As to hyaluronidase, while there is much controversy over whether hyaluronidase used to dissolve unwanted injected hyaluronic acid fillers can cause atrophy in native hyaluronic acid, I have personally encountered this and in fact sometimes use hyaluronidase as an adjunct when shrinking unwanted tissue, such as for double chins and I have used salt injections on occasion to treat individuals who have been overtreated or improperly treated elsewhere with hyaluronic acid fillers and subsequently experienced atrophy due to the hyaluronidase. It is a simple technique worth trying and gratifying when successful. However, many individuals will require re-filling with a hyaluronic acid filler to achieve optimal correction. Make sure that you are consulting with a board certified aesthetic physician with experience and expertise. Best of luck. .

If you have damage post injections I would suggest consulting with a board certified physician in order have your case properly assessed. Best, Dr. Emer. 

Indentations from HA may not be improved by injections saline to the area. Consider reasking your question with photos. Dr Joseph 

I would not expect a new indentation to occur prior to hyaluronidase injection. But if it were to, then I would probably recommend microneedling with PRP, fractional lasers or filler to treat the indentation. 

If you could elaborate further on what you are referring to in regards to damage from hyaluronidase that would be helpful. Also what location (presumably on the face) you are referring to. Photos are also important to figure out what the issue may be. 
All the best!