Thanks for these additional details.
1) Yes I agree the lump/swelling is a new symptom and it needs full attention. You require an MRI of the brain with and without contrast and that will tell us is there any structural pathology in the scalp or skull bone area that might be producing the swelling. It is less likely coming from the brain, but a structural pathology in the scalp/skull bone area can produce similar swelling.
2) The chances of a CSF leak are very less likely. However the MRI with contrast will help us in that regard too.
3) If MRI comes normal then there is a possibility that you might be experiencing what we call as autonomic trigeminal cephalgia. These are headaches that are associated with swelling, eye symptoms and nasal secretions as you mentioned. Cluster headache is an example although you do not have classical features. But then there are variants of cluster headache that can present like this.
So if MRI comes normal that is what I will suspect in you.
4) The preferred treatment for this kind of headache includes (not all these treatments together, just try any one agent and see if it helps if no help then try another agent);
A) For acute attacks (agents for immediate relief):
a) Lidocaine 4% solution. Use nasal dropper and instill 1 ml into the affected nose, repeat another dos after 10 minutes if necessary, 2 total doses/day.
b) 100% O2, 10 liters/minute x 10 minutes by non re-breathing mask (keep tank at home)
c) Tab Caffergot: starting dose 2 tablets, then to repeat 1 tablet at one hourly interval x 2 more doses, maximum per day 4 tablets, maximum per week 10 tablets.
B) Preventive agents: (to use this if headaches are frequent, not otherwise).
a) Tab Verapamil: Starting dose at 40 mg twice daily
b) Tab Depakote ER: Starting dose 250 mg at bed time. If you use this periodically you should undergo liver function tests & CBC (cell count) as this drug can affect the liver and blood cells rarely.
C) If nausea and/or vomiting present:
Tab Stemetil 5 mg, 1 to 3 times per day
Tab Phenergan 25 mg: 1 to 3 times per day.
So if MRI comes normal I will consider your headache as above (in addition you do have some migraine type headache too) and the treatment plan is as discussed above.
5) Yes I agree the PFO may require additional intervention if possible since its presence can make management of migraine headache difficult.
These are my opinions & recommendations based on the details provided, and if you are seeking a more elaborative discussion or have additional concerns then please ask any number of questions until you clarify all your doubts.
All the Best!