* Rock Smash is learned too late: You learn Rock Smash from the Move Tutor in Veilstone City after you've already beaten the Gym Leader. By this point, you've already cleared the Ravaged Path and are likely heading towards the next gym.
* The path is meant to be blocked: The Ravaged Path is designed to be a temporary obstacle, meant to guide you towards the next part of the story. It's not meant to be bypassed with Rock Smash.
To progress past the Ravaged Path, you need to follow the main story. You'll need to head towards the next gym leader and continue the main plotline. Eventually, the path will be cleared, and you can explore it at your leisure.
Let me know if you have any other questions about Pokemon Pearl!