it sounds like the geranium was close to death and as a result has gone into flower production to reproduce. if you want to push the leaves along then you can give it some liquid fish emulsion but if its only just started recovering you could dilute it to half normal strength and use it weekly or fortnightly until the leaves comes along, also if you cut some of the flowers off then it will take some of the stress off aswell.

I have had the same problem with 2 hanging baskets that are always in full sun on the south west corner of the house. This happens every year. I buy geraniums with normal size leaves then as the summer progresses the leaves get smaller and smaller and the leaf color changes from all green to green and rust colors. I figured it was intense heat and full sun that caused it. But I'm not sure. The ones that I put in the backyard (where they get sun and shade) don't do that.

Thanks Terri and Trancegemini for help with my geranium. I'll try the fish emulsion and move the hanging basket out of direct sunlight Maybe that will do the trick. I sure hope so!