No. Once you sign a full and final release of claims for your bodily injury claim, your case is closed. You cannot go back later and change your mind and get more money from the insurance company.
While there are some cases that can be settled on your own without an attorney, there are many more cases where a good personal injury attorney can in fact SAVE you thousands. That’s why it is always a good idea to at least speak with an attorney before settling your injury case on your own.