Do not rely only on the internet. Consult your family doctor or community nurse.
There does not appear to be (so far) any scientific basis* for the use of topical vinegar on a wasp sting. It is widely claimed as being of value in the treatment of wasp stings. The basis for the claim is folklore. My own experience of being stung by a wasp was that vinegar (e.g. malt vinegar) applied on a cotton pad for approximately 40 minutes completely relieved the pain of the sting. During that time removal of the vinegar soaked pad caused almost immediate return of the pain. A number of websites developed by Primary care Trusts in England suggest using topical vinegar but NHSDirect and PatientUK do not mention it. My concern is that while it seems helpful for pain relief initially after a sting it is on its own inadequate and insufficient treatment. So, while vinegar may help, and is unlikely to harm, the other comprehensive advice should also be followed.
*The suggested science behind use of vinegar is that the sting is alkaline and that vinegar as a mild, and readily available, acid may reduce pain by neutralizing the pH. On the basis of only one insect we have a possible result of alkaline sting but the picture shown may simply be alkaline abdominal contents.