Probably not doomed.
Cow dung, if not composted (i.e., aged) contains a lot of urine = urea. Even though urea is a potent nitrogen source, in higher quantities it reverses the osmotic balance and draws water out of the plant through the roots. This is known as fertilizer burn. The fertilizer granules add to this though they may take a bit longer to dissolve. Osmocote prills, on the other hand, release their contents slowly (over the span of months) and so aren't contributing to your problem.
It will help if you can scrape off all of the cow dung and fertilizer granules on the surface of the soil that you can. Then water repeatedly. Fill the pot to the top with water, let it drain, and repeat many times, lets say 10 times. Then wait two or three days and repeat if your plants are not already greening. You are trying to flush all that extra nitrogen salt from the soil. Once done, your roots will be able to adsorb water again and they will 'perk up'.
But, you are right. You committed a cardinal offense of gardening and horticulture in general, not just the world of Jasmines. What you need to understand is that plant roots take in mineral salts by an active biological process. This biological process needs to produce a higher concentration of the salt in the root cells than outside. If so, water then moves into the root cell by the chemical process of osmosis to balance the salt concentration inside the cell with the concentration on the outside (in the soil). Too much mineral salt on the outside makes water moves the other way, out of the root into the soil = 'fertilizer burn'.
It is very simple. A little fertilizer is a good thing. A lot of fertilizer is not.