Share Textures From a Similar SPP?

Hello.

I'm a student very new to all things 3D including substance, so forgive me if this is a stupid question. 

I found it necessary to make a sculptural amendment to part of a character model I'd already baked and textured in SP.

I was really pleased with the highly complex paint job I'd done on the head and wondered if it were possible to use that texture from the original session in the .spp of the revised model?

Any help would be really appreciated.

G.