You can also try bee-honey if you find to buy something 100% natural.
My mother use it on my welts many times in my childhood.
I don't know if was something placebo or not, but in my case was working and the stinging becomes bearable shortly.
The bad parts are:
1. The spanking marks/welts almost than don't disappear faster than normal.
2. The skin becomes sticky for several hours during which you can not sit down or to wear clothes.
When I was young I used to remain bottomless around the house up to the end of the day, but after I turned 12 or so, only in my room even when it was just family present in the house. With a sticky bottom, all you can do is to do some chores if you have some privacy or lie on your stomach while you reading or watching TV :)