It is unlikely that you will gain much height from now on, as bone maturity is at about 17 years of age. After your growth plates in bone fuse, there is no way that you can gain height. You should be happy with what you have, and by no means your height should undermine your self esteem.
In order to get the best of the growth phase you have left, consult an endocrinologist.
Hi..... Unfortunately, once you're done growing, that's pretty much it. Men grow height-wise until ~21 years old, although depending on the person they may experience slight changes until 25.
For someone in their later twenties, you're already not producing the regul ar pulsatile bursts of growth hormone needed to stimulate longitudinal growth, but even if an exogenous source was provided, the growth region of the bone known as the epiphyseal plate has already shut down, so you'd only grow laterally. If you get doses of growth hormone as an adult, you develop a condition known as acromegaly.