get my own back for my failure

[joham]

I was the middle child of three, but there was a gap of five years on either side, and I hardly saw my father before I was eight. For this and other reasons I was somewhat lonely. I had the lonely child's habit of making up stories and holding conversations with imaginary persons, and I think from the very start my literary ambitions were misxed up with the feeling of being isolated and undervalued. I knew that I had a natural ability with words and a power of facing unpleasant facts, and I felf that this created a sort of private world in which I could get my own back for my failure in everyday life.

What does the part in red bold mean? Is it an idiom? Thank you in advance.

[jlinger]

compensate for what I was missing

[David L.]

Jlinger:compensate for what I was missing
That's what the author intends.

However, the idiom 'to get my own back' means 'to do something unpleasant to someone because they have done something unpleasant to you".

I knew that I had a natural ability with words
Should have tempered his free-reining natural ability by consulting the dictionary more, perhaps?