Can causing trauma to the dorsal hump cause it to grow?

You probably have not affected the size of your nose.  It is possible that the pressure from the palm of your hand has caused a temporary inflammation of the nasal dorsum and therefore, the area looks bigger  than usual.  You did not cause the dorsal hump to grow.

 The dorsal hump is composed of both bone and cartilage. Manual pressure to the bridge of the nose will do nothing for the bone, but you could end up fracturing the upper lateral cartilage off of the  nasal bone. Closed rhinoplasty techniques can accomplish removing the dorsal hump. Once the hump is then removed, osteotomies of the nasal bones  will be required. For many examples of dorsal hump removal, please see the link and the video below

Dorsal humps are composed of bone and cartilage. Despite your best hopes, manual pressure on a hump with either your hand or any other device marketed for this purpose will not lead to a permanent reduction in the size of the hump. Your hump appeared smaller for a short time after pressing on it because you were just pushing fluid out of the area in the skin and causing the soft tissues to flatten for a short time. If you're doing this daily, you're causing some skin inflammation and swelling which is making the hump look bigger. This will go away once you stop irritating the area. If you are persistently unhappy with your nasal hump, your best option is to see a rhinoplasty surgeon in consultation to see what a rhinoplasty can do for you.