It is a must that you have your leak inspected by a professional, but there are things you can do until they arrive to limit the extent of the damage. If you see misplaced shingles, purchase asphalt roofing cement and apply generous amounts to the underside of the shingle. Do this if you see curled shingles as well, and press the shingles back in place. For peace of mind, contact a professional as they will have the tools, knowledge, and skills to fix roof leaks and will provide you with the right solutions.