100%Start of flowering stage? 1 mos old auto
Watered last four days ago, too much?how often are you watering? they look overwatered
Top dress means put more fresh medium on top of soil in pot?Let it dry as long as it takes .... top dress medium with same , then water in to feed. The extra nitro will help the stretch phase / branching. Around second week of flower , you can introduce a “ Bloom nute “ feed or another top dress.