How do I control BP & raynauds disease with hypothyroidism?

Open blood vessels. A vasodilator may be helpful for you. But your thyroid condition needs to be addressed first. See your medical doctor to make sure you are on proper medications.
Optimize hypothyroid. Optimize hypothyroidism and the other conditions are treated on its own merit.
Some meds are ok. A patient with raynaud's, thyroid disease, and high BP can work closely with his primary care, endocrinology, and rheumatology doctors to identify the things that trigger the vasospasm (in order to avoid them) and do trials of various drug therapies to see which drugs or combination of drugs give the best effect. Some "experimental" treatments can be tried. Some high BP meds are ok with raynaud's.