Mine did the same thing. It's growing back again, though and starting to bloom.
I noticed the old fashioned species type doesn't seem to have this problem.

Leslie,
You've had a whole lot of rain in your part of country, right? Is it the ground that isn't draining good enough for all the rain you've had, or is it that you've just had too much rain on the plant? Have you considered raising your Lantana so it gets better draining? Is your Lantana a periennial in Miss?
Pat

I have them in a raised bed, so I think the drainage is O.K. We had record-breaking rain totals in June. I live on the Coast, and the plants are perennial here, though they die back in the winter. The lantana is a Sunset or something like that. It looks like it's trying to bloom, but the buds don't open and the leaves just look terrible. I tried cutting it back a little, but the new leaves look bad, too. Thanks.