Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain it seems that the symptoms of itching, swelling and dry cracked lips is due to side effect of the sunscreen that you are using..
I would suggest you to stop using the sunscreen immediately..
You should take anti allergics like levocetrizine or
Benadryl to relieve the allergic reactions like itching, swelling etc..
You can do cool compresses over the lips..
You can apply a thick coat of petroleum jelly over the lips or bees wax containing lip balm to lubricate the lips as well as it helps in locking moisture.
You can also take anti-inflammatory painkiller like
Ibuprofen..
Take
multivitamin supplements..
Avoid licking, sucking the lips as it will further evaporate moisture from lips and cause drying and chapping..
You should drink plenty of water..
Limit sun exposure or exposure of lips to dry and
cold or hot air..
In case if there is no improvement in a week
consult a Dermatologist and get evaluated..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.