Swelling between the vagina and anus.

I have IBS and have challenges on and off with bloating, bowl movements etc. I'm managing it with food and exercise. A week back I had another flare up and stomach pain for three days, gas, bloating etc but now there's no pain. I have external hemorrhoids and they are slightly itchy due to strained bowel movement. Yesterday I found a swelling between my vagina and anal region. There's no pain, no bleeding, just a swelling, right above my anus. It's soft and there are no lumps. I'm not sure what this is. I checked with a doc who said I could do a sitz bath and I don't need antibiotics as it's not an abscess and I have no symptoms and to watch for a while. Can you please help me understand what this could be and if it's dangerous. I'm very anxious. I'm 40, female, and my hemorrhoids came after delivery. I'm not overweight.I have no other conditions. Any help would be great. Thank you.