to sun exposure is not uncommon and you should remain positive that it would be treated.
The best way for escaping allergies is to stay away from the identified or possible allergens. In your case it is not possible to avoid the Sun comletely, but you should try and get out only in mild sun. Try to cover all skin surfaces of your body, as much as possible to avoid direct contact of sun rays and skin, including a face scarf when in bright sun.
The medications you are taking should be able to suppress the allergy, but continue them for 4-6 weeks. Keep some skin soothing agents with you and use ice to resist itching when get the rashes and marks.
This goes away with body getting sensitized to the allergic stimulation, on a limited amount , long term exposure. So a little bit of sun facing and mixing it with antiallergic medicines would help you in long term. Please try and remain patient about it .
Hope you do well!