If you grew locks because of a Nazerite vow, simply make a new vow. If you don't want to vow on your hair, vow on something else.
And honestly, Samson should have never lost his strength if it was based on his vow because Samson never cut his hair. Someone else did. If you or your parents make vow on something that could be outside of your control then that is a foolish vow.
There's a difference between saying "I will never cut my beard" and "my beard will never be cut".
To get around the first you could just go to a barber and ask for a shave. But the second could be done while you were sleeping.
But these kinds of vows were common in ancient times because of superstition. A man famously vowed to sacrifice the first thing that came to greet him when he got home and it was his daughter. What a stupid thing to vow. And instead of the man laughing at how stupid it was or thinking that sacrificing a person is murder, he did it with the expectation that society would think it was okay because he had to according to a vow he made.
There are reasons why lawyers exist today. Contracts have addendums and considerations. What if this happens? What if that happens? A vow is just a contract you make with whoever you're making it to. If you didn't put enough thought into it, that's your fault. But that doesn't mean an innocent child must die or that you can't take a job that could catch your hair on fire. It's 2020. It's okay to be smarter than people in ancient times because the point of history is that we should learn from it. Everything people did back then is not everything that we should copy. We should be able to see when it was good and when it was a mistake.
Yes, Samson made an oath. But he was also used his strength to rob and murder people. He was a serial killer. We tend to overlook this because we perceive these people to be his enemies but it wasn't at a time of war. This would be like me saying whites are my enemies because of the Civil War and so I'm allowed to go around killing them. Of course you can't say that. Of course that would be murder. And if anyone can't understand that then they aren't morally qualified to read these ancient stories.