It is 'slang' ! 'Spotch' refers to a slow thinker with limited wit that walks around looking lost. It could also refer to any spot on your body specially your back for you can not reach to scratch it. It has other meanings you can check on the link recommended by Harry. (Check if you meant 'spotch' or 'splotch')

I have never heard of this word, but as an English speaker, I would say it is a combination of spot + patch. You can find in this slang dictionary. I strongly advise you NOT to copy some of the words in this dictionary as they are very rude and, I think, mainly American: http://www.urbandictionary.com/