Hello anita,
Welcome to the Mrs. Clean Forum!
Yes, permanent marker can be tricky to remove, but it can usually be done.
What type of wall and bathtub are affected? Is it porcelain or fiberglass? Is the wall painted or part of the tub enclosure?
The Magic Eraser from Mr. Clean (which can be purchased at most major stores) works so well, I recommend trying it first. Just gently rub the Magic Eraser over the marks and, hopefully, watch them disappear!
If that doesn’t work, there are many other
tips for removing marker stains from different surfaces here.
Good Luck and let me know how it turns out!
Mrs. Clean