You are lucky to have a job no matter how small the pay package is. Thank God first.
My advice is this, make a comparison of cost of living in the two cities, consider possobility of other higher opportunities in the two cities, are u sure that the promise being made to u in Lagos is real? A bird at hand is more than 10 in the bush.
There are still a lot to consider like priority and job satisfaction, is the place u are now your dream or will it take u to ur dream land with time? You may consider comfortability and accommodation issue in lagos too. I am in Lagos and I know what i am saying.
In all, pray hard for God's direction.
Thanks