Most of the big name string manufacturers are very understanding, and willing to go the extra mile, if you politely email their customer service.
Explain that you mismeasured, and incorrectly cut the string slightly to short, and ask if you can purchase a single string directly from them, as you've had no luck finding a store that will sell you a single.
In all likelihood, they'll send you a free string (if you're really nice, and self deprecating, you'll sometimes get an additional complete set of strings thrown in for free).
I've had great experiences with both D'Addario, and Rotosound customer service in that regard, and Ernie Ball Music Man have a great customer service reputation, so I'd be surprised if that doesn't extend to Ernie Ball strings.
Explain that you mismeasured, and incorrectly cut the string slightly to short, and ask if you can purchase a single string directly from them, as you've had no luck finding a store that will sell you a single.
In all likelihood, they'll send you a free string (if you're really nice, and self deprecating, you'll sometimes get an additional complete set of strings thrown in for free).
I've had great experiences with both D'Addario, and Rotosound customer service in that regard, and Ernie Ball Music Man have a great customer service reputation, so I'd be surprised if that doesn't extend to Ernie Ball strings.