Cold limbs are from vasoconstriction (tightening of blood vessels) secondary to hypertension (high blood pressure) causing hypoperfusion (lack of blood flow) to the extremities. Stimulants raise your blood pressure and heart rate to sometimes dangerous levels. Do not try anything to raise them higher. Vasodilation (relaxation of blood vessels) can be promoted with heat, especially warm water. Take a hot shower before using or during comedown. Make sure your clothes are not too tight and that whatever position you're in allows for adequate blood flow to the extremities (don't sit with legs tightly crossed or sit on your foot or hold your head up with you hand for too long, etc.) The best solution is decrease your dosage, user over a shorter duration per session and overall, and check your blood pressure and heart rate before redosing if possible (choose a cutoff point that you feel comfortable with but medically I would definitely not exceed 190/100 or 140bpm).
Niacin will cause flushing (you'll feel warmer) but can raise blood pressure dangerously when on stimulants. Avoid. Ibuprofen will not affect your perfusion. It treats fever and mild pain/inflammation.
