Recover Damaged file

I opened a pdf file, made some changes in it (used the highlighter option to highlight some sentences in the pdf and inserted some comments) and then saved the document by overwriting the previous file. After some time i forced shut down my PC by long pressing the power button.

I tried to open the same file again after 6 hours but received the following message:

"Adobe acrobat reader could not open 'FILE NAME' because it is either not a supported file type or because the file has been damaged (for example, it was sent as an email attachment and was not correctly decoded)".

I do not understand why saving a file in Adobe Acrobat reader will damage the file. Please help me recover the file as it contained some very important information.

I tried many options to recover the same but failed. If required, I can send the file to adobe and adobe can send me back after repairing.