Answer: I'm sorry it has taken so long to answer your question.
First of all, these plants can be toxic so it is important to either relocate the plant or train the dog to stop eating it! (My cat likes to nibble on mine -- bad kitty!)
You can trim away any damaged leaves, in a short while the new growth will make the damage unnoticeable. Unfortunately, the leaves will not "repair" themselves.
In terms of encouraging the plant to grow and bloom, there are several reasons why a plant may slow down. One is a change in reduced light; sometimes the summer sun being higher in the sky results in less light actually reaching the plant. Next is a lack of fertility, where the plant could use a regular regime of fertilizer according to the label instructions during the growing season (less or none in winter when the lighting is least). Use a water soluble formulated for foliage plants and also that includes minor nutrients. This plant is somewhat sensitive to overfertilizing and a buildup of minerals in the soil, so you might want to leach the soil every few months as a precaution. Next would be overcrowding, and the plant needs to be either repotted into a larger pot or divided and replanted. These plants tend to lose some vigor with time and a plant that you have had for several years probably would be ready for division and/or repotting, especially if has grown a lot. I hope this helps you trouble shoot.
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