In the first instance you would need to contact your current GP surgery if you are staying in England as they may be able to offer you a virtual consultation. This can be a telephone consultation, video consultation or they may ask for you to send photos. They are able to send prescriptions, if needed via EPS to a chemist near to where you are staying.
If you are ill while away from home outside of England or if you are not registered with a doctor but need to see one, you can receive emergency treatment from the local GP practice for 14 days. After 14 days you will need to register as a temporary or permanent patient.
To register as a temporary patient simply contact the local practice you wish to use. Practices do not have to accept you as a temporary patient although they do have an obligation to offer emergency treatment. You cannot register as a temporary patient at a practice in the town or area where you are already registered.