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Look down close to the skin and see if you can spot any legs indicating this is a tick.
You can see a tick here
and another here
You can read about tick removal here
I usualy put some neosporin or triple antibiotic on a spot where I have removed a tick.
Later you would want your vet to check for tick carried diseases and you may want to get your dog on tick prevention such as Frontline or a tick collar with Amitraz such as Preventic or Tick Detach.
If this is not a tick then you should have your vet check the lump out. It may be just a skin tag but it might be something that needs to be removed and usually if that is the case you want it removed while its as small as possible.
Hope this helps you!