If the affected wood is ply and it's been soaked through a layer then the ply will start to delaminate. Really need to cut out the bad wood and begin reconstructing.

My first experience was a friends Super Sportster 90 that had years of fuel soaking. Symptom was that the wood had a green tint to it (green fuel), a slimy feel and the covering was pulling up. He had recently bought the plane at auction (really cheap price). The first landing was a simple nose over. Damage? The fuse sides back to the former located just behind the wing saddle delaminated instantaneously. Reconstruction / recovering and it's flying nicely today.

Let us now how your renovation project goes. Always an excuse to recover with a new scheme - like Don's club trainer.