your sentence is incomplete ,so it depends on the pronoun 'That' refer to what in your sentence?
It will make the problem either worse or better.
That will help the problem.
Does this mean that it will makes things better or worse?
your sentence is incomplete ,so it depends on the pronoun 'That' refer to what in your sentence?
It will make the problem either worse or better.
In all likelihood, it'll make things better.