If you have enough sodium hydroxide on the ground, and it is somewhere you walk with bare feet or have kids or dogs walking, I would recommend neutralizing. You could clean it many many times with water, to dilute it, but I don't know what floor it is on.
Is it on a wooden floor inside or something? Outside on a concrete floor in the garage?
If I am reading you correctly, the concentration solution is 250g NaOH into 8000mL (8L) of water, which is a 0.77M solution of Sodium hydroxide, not very concentrated, but could cause some chemical burns as its pH is 13.9 (14) for all intensive purposes.
Now I don't get what you mean by
I mixed 3g with 100 ml of water
did you take 3g of the concentrated solution (3mL?) and put it in 100mL of water? Or did you take 3g of NaOH and put it in 100mL of water?
Now, if you have 250g NaOH per 8L, then you have 30.8g NaOH per 1L, and 3.08g per 100mL, or 0.031g per 1 mL so if you took 3mL of the concentrated solution (about 3 grams) and put it into 100mL, you would only have about 0.093 ( about 1/10th of a gram) of sodium hydroxide in the solution. For that, I would say don't even bother neutralizing it, just dump some water on it and try and soak it up.
Either way, it looks like you are dealing with small amounts of NaOH and water dilution is your best bet. If it is where children or pets walk, then sure maybe a little vinegar or citric acid diluted in water might help, but it would also smell for a while.