It may be De-Quervein syndrome due to repetitive action of wrist or thumb... can say overuse injury.
It may cause weakness in grip & wrist region.
Next Steps
Apply ice Pack for 10min 3-4 times in a day.
Apply Dynapar gel & Wrist support with thumb support.
T.Etoshine 90 once in a day for 3 days.
If not relieved in 2 or 3 days consult any Good Physiotherapist or Good Ortho surgeon followed by Physiotherapy sessions[Mainly Ultrasound therapy, Ice Pack & LASER] followed by exercises when inflammatory signs get reduced very much.
Health Tips
Avoid driving/riding
Avoid Fine movements like Mobile use,Piano/Guitar playing etc.
Avoid Gripping actions,Push/Pull activities.