Oleander with burnt looking leaves?

You may just have to wait. I had a tender plant freeze one time, but I was told not to cut off the dead stuff right away. I waited, and in spring I did cut back the dead stuff after I detected new growth starting to show. It came back slowly and now it's fine. Also, my neighbor had oleander that was getting really brown. He discovered gophers were eating the roots and killing it from beneath the ground. Also, once he watered the other one more, it looked better. People say to water well before frost is expected, because cold tends to dry out plants. The black bud ends & curled leaves sound more like a fungus or parasite. (Or perhaps the plastic bag trapped in moisture and they mildewed). Pick off some sample leaves and take it to a good nursery or to the county extension office for advice. I hope that this may help you.