Q.Crape myrtle trunk bumps
After normal bark peeling, saw many small bumps,whitish,up and down on trunk that was underneath, plus a long wound on the trunk

It appears your tree may have had an injury; either mechanical or perhaps from sun scorch.
I could not find any information on the bumps that appear on the trunks of your trees.
Are the trees showing any other signs of stress? Yellowing of leaves, leaf spots?
I would show the image to your County Extension Office, they may have information on local issues with Crepe Myrtle.
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/crepe-myrtle-care.htm
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/yellowing-crepe-myrtle-leaves.htm
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/bark-shedding-crepe-myrtle.htm
https://www.gardeningknowhow.com/extension-search/