I am not sure if I understood: did you keep planter inside during the winter? In the detached garage... little sunlight, really, but protected from freezing cold. And I only watered every 2-3 weeks. I had 3 Royal Ruby, 3 Black, and 3 Cobweb Buttons sempervivum in there, and all are black and appear rotted now. I also had Ice Plant and a Firestorm sedum in there that appear dead, too. The Lemon Balm did fine, though, and the Dragon's Blood stonecrop appears to be coming back. I figured that the sempervivum would be fine either way, I mainly just moved it to the garage to protect the Lemon Balm and Ice Plant! I had another small planter of Royal Rubies left outside, and it did just fine. So I suspect that the problem had less to do with the temperature, and more to do with either low light or the lack of water? Either way, I'll give it some more time and see what's what :-D The chicks here confused me, though, because the ones I've transplanted before had grown outward instead of straight up.

When I behead plants & pot up cutting, I start watering when roots start groowing. That is most often when new growth start appearing. So good you are not watering rootless cutting. Black scarrings coul be from the damage very young leaves had on them, often barely visible. If it is on brand new leaves that grew since, I would suspect a pest. Many are tiny & hard to see. Also when spraying with anything, plant should be kept out of direct sunlight. RA dries up fast, but I would keep plant out of direct sun for at least 5-8hrs. Some plants react to it very fast, here is one I damaged by spraying with RA...it has thin leaves: Damage like that doesn't get repaired, but new leaves will grow... Finally, could be a damage from too much light; all plants should be acclimated.

That's an echeveria? Echies are supposed to look a rosette shape, and yours is stretching up like that because it does not have enough light. Any possibility of a brighter window location? Echeverias often lose lower leaves as they grow, so I wouldn't worry too much about that. Light is your problem. And possibly your pot..... I prefer a straight sided terracotta pot to the style you are using. I hope your pot has a hole in the bottom for drainage because that is the best condition for any plant, to have that excess water drainage benefit.

Once a week is too often to water and that could be the problem; succulents like to be dry. They store water in their fleshy leaves, and even though the soil looks dry to us, they have plenty to live on. That was a lesson I learned by killing quite a few aloe by over watering. I only water my succulents every couple of weeks, sometimes longer if I forget. Also, it needs to be planted in a medium that drains quickly and doesn't stay wet. There are potting mixes made especially for succulents, or you can mix your own. Does the pot it's in have a drainage hole? It's very important that water is allowed to drain out of the pot, or planter. I hope you can save your pretty plant.