Cored wood bulkhead on C&C 24
While pumping the bilge on my C&C 24 I noticed a couple of raised blisters on my interior cabin wall near the starboard window. I have a tarp over the cabin to the mast. Could I have moisture entering the bulkhead from either the mast or handrail and expanding as it froze in the bulkhead? Is there any way to repair or reduce damage? thanks.