I recently had to pluck out almost all the leaves of my Poinsettia which got burnt due to a little bit extra use of neem oil. The stem looks very bare now. There hasn't been any new growth of leaves since then. I've waited for around 15 days but the plant doesn't show any signs of growth. The top part of the plant (which was unaffected by the oil solution) has been giving out healthy leaves though. Is there any way I can encourage leaf growth on the stem and branches too? Yesterday I watered it with a very dilute solution of sea weed fertiliser.
I would wait another month or two, to see if anything happens naturally, and to give the plant plenty of time to recover.
If it hasn't started to regrow the way you want after that, you can encourage it to grow from lower down a branch by cutting off the tip. You only need to cut off the top pair of leaves. Try that with one or two branches first before you do it to the whole plant.
If that doesn't work, you can grow new plants from cuttings. The traditional way is to cut about 4 inches (10 cm) from the tip of a stem, remove all the leaves except the top four. You can plant several cuttings round the edge of a pot, and then put the pot in a transparent plastic bag to stop them drying out before they grow roots. (The bag doesn't have to be transparent, but that way you can see what is happening without opening it.) They should start to grow within a few weeks. Alternatively, you can take a longer piece (up to a foot) of more "woody" stem that is beginning to change colour from green to brown, remove ALL the leaves, and plant half the length of the stem in a pot. Make sure you plant them the right way up!. Again you can put several in one pot, and they should start to grow leaves within two or three weeks.