Can't be sure but some of your damage looks like birds pecking/scraping your peel to get oils. It doesn't ruin the fruit but sure makes it look awful. Boat-tailed grackles are the culprit in my area and they like my lemons. Some years, they don't mess with them and other years they are bad. They tend to damage the higher fruit the most.

I also see some marring of the fruit caused by wind rubbing the fruit against other branches and especially against the thorns that are plentiful on my Ponderosa lemons.

I was going to say the same as John. I have had a few of these this year, mainly from fruits rubbing against each other or against branches when there's wind.

The first picture looks like tear stain melanose (TSM). TSM is only important when the fruit is going to be marketed to the public in the commercial market'

Has this tree had any dead wood (branches, twigs, etc.) of any kind recently? Melanose is most susceptible on grapefruit and lemons. The fruit is still good for human consumption.

Thank you for your comments. Branches, twigs, leaves all look good. When cut open, the fruit looks good as well. We have had a lot of high winds during the fruit growing season.

Birds... when the fruits are smaller and green, small birds peck the fruit to use the oil to put on their feathers; it is a natural mite repellent. Mostly cosmetic issue; the fruit is undamaged. You can prevent it with a bird net during the juvenile period of the fruit.