Your penis will look and feel heavier.
However, if you jelq with too low erection level, your gains will be very uneven.
Add a stretch: If part of your goal is to gain length, then give your penis a quick tug after each jelq.
If you allow for enough rest time between your workout sessions, these micro-tears will heal and will result in new tissue growth.
Penis growth exercises abound on the Internet and with a little bit of research, you can find sites, like this one, that will give you the skinny on the top free penis growth exercises around.
Doing jelqing is not different.
Just as with edging, this process can be repeated many times over as desired.
I do not recommend ejaculating before, during, or after your penis enlargement routine, whether it includes jelqing exercise or not.