I can only tell you what I do and you have to decide but first I have a couple of questions. What incubator, how do you add water, and do you know what the humidity is running? Do you have something to candle with?
Now, if an egg has pipped or even started zipping and has made no progress for several days I try to listen for signs of life, check the membrane for drying, and usually start giving a little help by finishing the zip including perforating the membrane. It usually helps to moisten the membrane with a damp cloth, eye dropper, etc. because most of the time the chick is stuck to it. Be careful not to drown the chick and try and let it do most of the work like lifting the 'lid' and kicking out of the shell. Just know going in that you win some, you lose some. (I usually look at it like I was going to lose all of them if I did nothing anyway.) I have had some chicks that I've helped do better than some that I thought were 'healthy' chicks that hatched on their own and are now producers.
Whatever you decide, best of luck and don't give up after one bad experience.
