Oh sorry to hear about that! Your theory makes sense, that's very unfortunate timing, an interesting hole in our game flow. Your workaround hack sounds like should be safe - I think that painting has no real purpose, but I can't say for sure what might happen if you tried to paint a new one now.
I believe our inventory debug hack should also still be available in the game, which we added as an emergency backup in the case that anyone hit any unforeseen issues with the inventory system. I believe it can be activated by holding the Spacebar key in the crafting bench screen for 10 seconds straight, which then lets you add any item to your inventory - just be careful because you could probably break your game if you over-used that and flooded your inventory with too many items.