Hi If you notice persistent forehead sweating. Get  cardiovascular examination done once by a pediatrician or pediatric cardiologist

If she is passing urine adequately then sweating is not an issue Kindly get a detailed Cardiac Examination done when you visit your Pediatrician next time.

If there is persistent sweating, you have to get a cardiologist opinion and an echo done. There is nothing to worry about. For some babies, it is normal. Usually if there is a cardiac issue, baby won't gain weight normally and have constant infections or be irritable. But your baby's weight is good for age..