I created a signature but there is a large question mark and a head image overlaid on it. How do i get rid of this?

I created a signature using signpad on Acrobat Pro 8 and it looks normal but this is what it shows up as when I open the PDF in Acrobat Reader DC:

I tried validating the signature, and it replaced the above image with a large green tick instead. How can I get rid of the image entirely?

Please help

Bob