No, not really, but I trust the horse manure was well rotted as otherwise you are going to have a problem.

If it is fresh scrape it off and set it aside to cure further. Do not turn fresh manure into the plot because it will make the soil much to acid to grow anything with success and then you will be spending too much time doing a juggling act trying to get the ph back to where it should be with amendments.

If your soil is heavy, then it would have been best to dig it in the autumn. On light soils, best to dig in spring as winter rains will wash away nutrients. But always avoid manure on the areas in which you propose growing root vegetables. I would leave for now as soil will be wet and any disturbance will cause compaction of soil.