It makes sense that your hot flashes worsened because the ovaries produce hormones into a woman's 80's if she has all her parts. Unfortunately, women are misled about the non-reproductive functions of their uterus and ovaries.
I had a hysterectomy at age 49 and all hell broke loose although I was still having regular periods.
I had a hysterectomy a few months ago in August. My GYN removed EVERYTHING except for a tiny portion of my cervix for a safety measure. He prescribed Premarin 1.25mg. for a month. Since, I haven't had hot flashes, mood swings, or vagina dryness. I was 47 at the time of surgery. The thing I've experienced is I get mild cramps during what would normally be my time of the month, however, with each passing month it is becoming less and less. I feel so much better now!!!!
I am 43 and had a full hysterectomy 6 weeks ago but prior to that was having menopause symptoms. I went on the Vivelle hormone replacement patch the day of surgery and everything went away. Even all my menopausal symptoms prior to my surgery. I don't have any issues at all. I still am having some days where I will feel "off"'and highly emotional (a commercial will make me cry) but my doctor said that was simply a residual effect of my old hormones still lingering in my system and once they are gone I will completely level out. I hope this helps. Take care.