Hi Jan,
Yes, definitely get a referral to a dermatologist who specialises in that area. They will be able to diagnose and put your mind at rest. I too have had the problem get worse in the summer. There are the obvious things to do like , cotton knickers , if one needs panti liners use the unscented ones ( Sainsbury's own are good), and change them regularly if you get a bit sweaty. Do not over wash and do not use soap down there. No bubble bath and not very hot water or baths as this dries out the skin. Moisturise twice a day with Hydromol,( Vaseline apparently is more of a barrier than a moisturiser) wear a skirt if you can.
No one should have to suffer like that, and it is usually because we do not do the right things to start with ( no proper diagnosis) and the problem never goes away or doesn't get better. Also if it does get better we stop and it comes back!
Definitely ask for a referral !
Pepperminty xx