Ok, that helps a little, but it still makes no sense. Whether you are shedding virus through your breath or not, in both cases, you don’t need to worry about infecting yourself through your arm!
Think it through in detail.
Case A: You are infected. You can’t infect yourself worse than you already are. You just need to worry about infecting other people. Isolate yourself, etc.
Case B: You are not infected. You can’t infect anything. Relax.
As for getting infected by other things: Put a bandage on your hole. When it has a scab on it, you don’t need a bandage on it.