Answer: It doesn't sound good for your tree! As you've learned, plants growing in containers need some special care, especially when it comes to fertilizer application. Because the roots are in a confined area they are more susceptible to burn if too much fertilizer is used. It's always best to use 1/2 to 1/4 strength fertilizer and feed more often than to apply it full strength.
You may be able to save your tree by unpotting it, washing all the soil off the roots and then repotting it in fresh soil. It may take some time, but the tree might recover and produce new leaves and fruits. Pick off the affected fruit, since it won't ripen properly anyway. Removing the fruit will help direct the plant's energy into recovering from the over-fertilization rather than into developing the fruits.
Hope your tree perks up soon!
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