It's uncommon for sunburn to cause a total collapse of a plant, so the issue is likely to be found in watering habits. I'd say the odds significantly favor the issue being related to the effects of over-watering. If the issue is indeed related to over-watering, as I suspect, whether the plant makes it or not depends on how severely the roots are damaged. The best course is to depot the plant, inspect the roots for rot, trim any roots visibly compromised or suspected of infection by rot, and repot into an appropriate size container with an appropriate soil. The alternate, which offers a reduced expectation of an end result that's favorable, would be to depot the plant if the soil is wet (as opposed to damp), and place the root mass on a stack of newspaper, paper bags, an old towel .... to dry down before returning it to its container, after which you would monitor water needs more carefully. I should have asked if you fertilized the plant since acquiring it. If yes, it could be the reason or play a part in the problem. If you did fertilize, please describe what you used and at what strength. Al

You're probably doing fine. The flowers, also called spathes come and go. Eventually, if you keep your plant happy, it will grow new ones. Just enjoy those beautiful, new, luscious green leaves. -Rachel

I agree that the peace lilly and betta look great in a vase, but it isn't practical for keeping a healthy, happy fish long-term. The plant eventually grows to block the opening of the jar, thus preventing O2 from reaching the surface of the water where the fish can gulp it, or it can diffuse. You must constantly prune plant, roots, leaves and stems to keep a healthy opening for air circulation. You also need to pull the plant out to change at least 20% of the betta's water daily to prevent ammonia buildup and an unhealthy fish. It is a pain, and the novelty quickly wears off, especially if your fish doesn't appear healthy or happy. I tried it once, but within a month I got the fish a 2.5 gallon aquarium with heat and filtration, faux driftwood and other items so he had things to interest him and places to hide. I also got him little ramshorn snails and bloodworms to hunt. His response was to start building bubble nests, get much more active, and appear much happier. I still used his tank to root plants because it was great for that, and he liked the roots, but I never let it take up more than maybe 20% of his space. There is nothing to keep you from placing the fish and plant in a vase for a holiday center piece, or a party, but for his health, put him back in the tank afterward. For more information on keeping bettas in vases, check in at the forums of Badman's Tropical Fish - badmanstropicalfish.com/forum.

In most cases, over-watering and/or a high level of dissolved solids (salts) in the soil solution is inhibiting the plant's ability to efficiently move water to the plant's most distal parts - leaf tips and margins. This is usually due to either a lack of oxygen (due to too much water in the soil) or a high level of salts making it difficult for water to make its way into plant cells. Your plant might grouse a bit if you repot again into a more appropriate medium, but it's better than battling your soil for control of your plant's vitality for the next 12 months. Al