There is good reason. I have posted about a possible pimp and am genuinely worried.
Changing the account "handle" won't change anything - it won't separate post from profile. You would need a complete new profile to do that.
Now lets look at the problem.
Which post or posts are you worried about?
Have you met this pimp? Does he know you, and does he know it's you who posted?
Or do the girls know it's you?
Where did the meet happen?
Do any of them have your real name, address, phone number or car reg?
Did you use a punting phone?
Have any threats been made?